The Geography Division has prepared this document to help U.S. Census Bureau staff reply to questions data users may ask about changes related to the geographic entities for which Census 2000 provides data. The text should be used in conjunction with the accompanying special glossary.
The text, in a question-and-answer format, is divided into the following categories:
Note: Each of these entities is discussed in the appropriate section.
Note: See the sections on census tracts and census blocks regarding the treatment of crews of vessels for Census 2000.
Note: Also see text for state legislative districts in the section, Other Geographic Entities.
A. As the result of legal actions by state governments, two legal entities
that the U.S. Census Bureau treated as statistically equivalent to counties were
added and two were dropped, and one county and one statistically equivalent entity
were renamed, as follows:
Q. I can't find data for:
Dade County, Florida (FIPS county code 025).
A. This county was legally renamed Miami-Dade
County (FIPS county code 086) on November 13, 1997.
Skagway-Yakutat-Angoon Census Area, Alaska (FIPS county code 231).
A. When the state of Alaska established Yakutat as "a city and borough" on September 22, 1992, the Yakutat area had to be deleted from the Skagway-Yakutat-Angoon Census Area.
The remainder of this census area subsequently was renamed
Skagway-Hoonah-Angoon (FIPS county code 232).
South Boston city, Virginia (FIPS county code 780).
A. The state of Virginia legally designated this independent
city as a town on June 30, 1995, at which time it became part of Halifax
County (FIPS county code 083).
Yellowstone National Park, Montana (FIPS county code 113).
A. On November 7, 1997, the state of Montana legally realigned the
boundaries of Gallatin and Park Counties (FIPS county codes 031 and 067, respectively)
so they contained the part of the national park located in this state.
Q. I notice that some county subdivisions in the 1990 census have disappeared, and others have names that are new, for Census 2000. What happened?
A. Changes to county subdivisions can occur for a variety of reasons -
Q. I notice that many CDPs have fewer than 1,000 people. Aren't most CDPs supposed to have at least 1,000 people?
A. That was the 1990 census rule for CDPs in the lower 48 states, except those on American Indian reservations. For Census 2000, the U.S. Census Bureau dropped this requirement, and a CDP anywhere in the United States, Puerto Rico, and the Island Areas can be any population size.
Q. I notice that some places in the 1990 census are not in Census 2000, and others have names that are new for Census 2000. What happened?
A. In addition to states establishing new incorporated places, these entities can be changed by legal action that results in some being disincorporated, merged, or renamed. CDPs may be dropped from the census because their area was included within newly incorporated places or they were annexed, in whole or substantial part, to existing incorporated places; also, some were merged, renamed, or dropped by the local and tribal governments that reviewed the CDPs for Census 2000.
Q. The 1990 census included six consolidated cities, but now there are seven. But I notice that Jacksonville, Florida is no longer included as a consolidated city. What changed?
A. Athens-Clarke County and Augusta-Richmond County - both in Georgia - became consolidated cities in the 1990s. As for Jacksonville, the local governments brought to our attention that legislation in 1978 and 1992 changed the relationship of Jacksonville city to the other incorporated places in Duval County. While the consolidated government provides county-level services to these places, it has no jurisdiction over the population or territory within their boundaries; therefore, it no longer qualifies as a consolidated city.
Q. For the 1990 census, the data files included the Census Bureau's 4-digit place codes. I can't find these on the Census 2000 data files.
A. The U.S. Census Bureau announced, in conjunction with the release of the 1990 census data products, that the 4-digit census codes were appearing for the last time. Data products showed the 5-digit FIPS codes as well, thereby providing data users with a last, one-time bridge between the two sets of codes. Census 2000 displays only the 5-digit FIPS codes in documents and files available to the public.
Q. I can't find some 5-digit place codes that were used for the 1990 census, or the 5-digit code for a place in Census 2000 is different from the 1990 census code for the same place.
A. Place codes are assigned in alphabetical order within each state. Some places had a name change, which usually required a new code to sequence the new name appropriately in the alphabetic list. A few codes had to be changed to accommodate the insertion of new names into their proper alphabetical location in the list.
Q. Why do I find census data for a Yakutat CDP rather than a Yakutat city in the Yakutat City and Borough?
A. Despite the legal designation, the state of Alaska did not establish a city in this entity because it is a "non-unified home rule borough." Instead, a census designated place was delineated for its built-up portion.
Q. For the 1990 census, federal and state reservations were listed together. Now they are listed separately. Why is that?
A. Federal tribes asked the U.S. Census Bureau to provide separate data tabulations for these two different types of American Indian entities. The Census Bureau facilitated this by assigning a new, unique set of codes to the state reservations.
Q. For the 1990 census, federal and state tribes that did not have a land base were listed together as tribal designated statistical areas. What happened to the state tribes?
A. For all tribes that did not have a land base (see footnote 1), the 1990 census referred to the geographic entities that were specially delineated to encompass the areas related to such tribes as tribal designated statistical areas (TDSAs). The federally recognized tribes asked the U.S. Census Bureau to tabulate their data separately from the tribes recognized only by state governments. Therefore, areas delineated for state tribes are shown in Census 2000 as a new type of geographic entity called state designated American Indian statistical areas (SDAISAs).
Q. Does the Census Bureau still get its information for tribes recognized by the U.S. government from the federal government's Bureau of Indian Affairs (BIA)?
A. The BIA is still the source of the inventory of federally recognized tribes. For Census 2000, the U.S. Census Bureau relied entirely on the officials of tribes with a land base, rather than also involving BIA staff, to review the legal boundaries already in the Census Bureau's records. The BIA was asked to participate only if the Census Bureau needed additional information. The Census Bureau still relied on the BIA, as well as tribal and other government agencies, to assist in identifying a first set of boundaries for federally recognized tribes whose lands it did not have on record.
Q. I notice that the Census Bureau provides data for several types of American Indian entities that have a land base. Some of these appear to be new for Census 2000.
A. Several types of reservations are new for Census 2000: Indian community, Indian village, ranch, and village. Also, the terminology was changed for two entities: tribal jurisdiction statistical area (TJSA) was changed to Oklahoma tribal statistical area (OTSA) to avoid any perception that these statistical entities reflect any type of legal status, and joint area was changed to joint use area to better reflect the common usage of overlapping tribal lands.
Q. Do the American Indian entities recognized in Census 2000 cover the same area as those in the 1990 census?
A. Many do, but some do not. The U.S. Census Bureau offered tribal and state officials the opportunity to review and revise the boundaries of the American Indian entities that it had used for the 1990 census.
Q. My tribe (or a member of my tribe) owns land next to the reservation. Why aren't these properties included in the data for Census 2000?
A. The U.S. Census Bureau provides data for off-reservation property related to a tribe, or an individual member of that tribe, if such land has been placed in trust with the federal government and is reported to the Census Bureau. The Census Bureau's reference to trust land applies to both tribal and individual off-reservation trust land.
Q. What happened to tribal jurisdiction statistical areas (TJSAs)?
A. To avoid any perception that these statistical entities reflect a type of legal status, the U.S. Census Bureau changed the term to Oklahoma tribal statistical areas (OTSAs).
Q. I notice that one tribal designated statistical area (TDSA) is located in more than one state. I thought that TDSAs had to be in one state.
A. In order to reflect the actual situation on the ground, and because TDSAs now refer only to tribes recognized by the federal government but do not have a land base, the U.S. Census Bureau changed the rule for Census 2000. Only the TDSA for the Pokagon Band of Potawatomi (census code 8670) is located in two states (Indiana and Michigan) for Census 2000.
Q. What are American Indian tribal subdivisions? Didn't the Census Bureau tabulate data for such areas in a previous census?
A. The U.S. Census Bureau offered every federally recognized tribe with a land base the opportunity to submit the boundaries of one set of legally defined internal administrative entities so that Census 2000 could provide data for them. The program also applied to the Oklahoma tribal statistical areas (OTSAs). The subdivisions had to have legally defined boundaries that were in effect on January 1, 2000, and could encompass only the area within 1) a reservation and/or off-reservation trust land or 2) an OTSA. Tribes delineated these entities for 21 reservations and 1 OTSA for Census 2000. The Census Bureau tabulated (but did not publish) 1980 census data for American Indian subreservation areas.
Q. Is every Alaska Native village (ANV) represented by an Alaska Native village statistical area (ANVSA) for Census 2000?
A. No. Thirteen ANVs that were not delineated as ANVSAs for the 1990 census were given the opportunity to delineate ANVSAs for Census 2000, but only three chose to do so.Q. Do the Alaska Native village statistical areas (ANVSAs) recognized in Census 2000 cover the same area as those in the 1990 census?
A. Most do, but some do not. The U.S. Census Bureau offered officials of the Alaska Native villages (ANVs) and Alaska Native Regional Corporations (ANRCs) the opportunity to review and revise the boundaries of the 1990 census ANVSAs. In addition, for ANVs for which the Census Bureau did not get a response from either an ANV or an ANRC, it reviewed the 1990 census ANVSA, and may have revised the previous boundary if appropriate. Also, the Census Bureau learned that 15 entities that the 1990 census had treated as ANVSAs had actually not been legally established as ANVs under the Alaska Native Claims Settlement Act, and so it did not report them as ANVSAs for Census 2000; three of these qualified to be redelineated as tribal designated statistical areas, and one (Tetlin) did so.
Q. What are Hawaiian home lands?
A. Hawaiian home lands are public lands held in trust by the state of Hawaii for the benefit of native Hawaiians; that is, people with at least one half Hawaiian ancestry. A Hawaiian home land is not a governmental unit; rather, it is a specific tract of land that has a legally defined boundary and is owned by the state. The state, as authorized by the Hawaiian Homes Commission Act passed by the U.S. Congress in 1920, may lease these tracts of land to one or more native Hawaiians for any activity authorized by state law. Data users identified a need for census information for these geographic entities, so the U.S. Census Bureau agreed to recognize the 61 home lands for the first time in the data tabulations from Census 2000.
Q. Why did many of the codes for American Indian/Alaska Native areas change from those used for the 1990 census?
A. The U.S. Census Bureau changed its codes to accommodate the several types of areas recognized as separate entities for Census 2000. The changes are as follows:
| Entity Type | Census 2000 Code Range | 1990 Census Code Range |
|---|---|---|
| federally recognized American Indian reservation and/or off-reservation trust land | 0001-4999 | 0001-4999 |
| Hawaiian home land | 5000-5499 | NA |
| Oklahoma tribal statistical area (2000), tribal jurisdiction statistical area (1990) | 5500-5999 | 5000-5999 |
| Alaska Native village statistical area | 6000-7999 | 6000-8999 |
| tribal designated statistical area | 8000-8999 | 9000-9998 |
| state recognized American Indian reservation | 9000-9499 | included in 0001-4999 |
| state designated American Indian statistical area | 9500-9998 | included in 9000-9998 |
Note: Also see special information about census tracts for American Indian entities in the next section.
Q. What is new about census tracts for Census 2000?
A. The criteria for delineating census tracts are essentially the same as for the 1990 census. However--
Note: Also see special information about census tracts for crews of vessels and American Indian entities below.
Q. Data for crews of vessels used to be available in separate census tracts. Where do I find these data now?
A. For previous censuses, the U.S. Census Bureau assigned the population aboard merchant and military ships related to a port facility or a naval or Coast Guard base the crews-of-vessels population to a census tract that was represented on Census Bureau maps by an imaginary area in the waters adjacent to that facility or base. The basic census tract number was derived from the land area where the facility or base was located, followed by a .99 suffix; for example, a naval base physically located in census tract 5 would have data for its ships' crews assigned to census tract 5.99, with the .99 uniquely identifying this tract as one that contained data only for the population of ships rather than local residents. For Census 2000, the crews-of-vessels population is assigned to the land census tract that contains the base, facility, dock, or pier related to the ship, or adjoins the related water body. To simplify geographic display and user understanding, the Census Bureau decided that a separate geographic designation was neither necessary nor desirable. In the data, the Census Bureau highlights the fact that a census tract contains shipboard population by including a special group quarters code for that population. The .99 suffix is not used for Census 2000.
Q. I notice that some census tracts are not in the numerical order of the other census tracts in a county - census tracts numbered in the 9400 series.
A. For Census 2000, the numbers 9400 to 9499 are reserved for census tracts related to federally recognized American Indian reservations and off-reservation trust lands, and are used primarily for census tracts that cross a county line. This ensures that American Indian lands will have a consistency of census tract numbers where a reservation and/or off-reservation trust lands are located in more than one state or county, and enables the U.S. Census Bureau to present census tract data uniquely for American Indian entities without regard for state or county lines, while maintaining the uniqueness of the census tract numbers within a county. The Census Bureau refers to any census tract, regardless of its number, that specifically represents an American Indian entity for data presentation purposes as a tribal census tract.
Q. Some block groups don't seem to be geographically comparable between the 1990 and 2000 censuses.
A. The criteria for delineating census block groups (BGs) for Census 2000 were essentially the same as for the 1990 census. However, BGs for the 1990 census were primarily delineated by the U.S. Census Bureau, especially in counties that had block numbering areas (BNAs). Because these BGs might not be meaningful for local data users, the Census Bureau urged local and tribal officials to review and revise the BGs for Census 2000 to ensure that the data for these entities would be more useful; therefore, it imposed no comparability requirement. Furthermore, it encouraged the officials to merge 1990 census BGs if they contained fewer than 600 people. The Census Bureau also permitted tribal officials to continue a BG across a county line within a tribal census tract; these are referred to as tribal BGs.
Q. Some block groups don't seem to be numerically comparable for the same area between the 1990 and 2000 censuses.
A. Deleting BGs could result in gaps in the numbering system; because the Census Bureau preferred to have numerically sequential BGs adjacent to each other, it encouraged the renumbering of BGs to eliminate gaps. Thus, if a participant did not indicate a desire to retain the existing BG numbers, a BG number for Census 2000 might not refer to the same approximate area as the 1990 census.
Q. Are there any other differences regarding Census 2000 block numbers?
A. Whereas the first block number in a 1990 census block group usually ended in "01," the first block number in a Census 2000 block group is usually assigned a number ending in "000." Also, every water body is now assigned a block number in the block group within which it is located - either the block number of the adjacent land area or its own unique number. For the 1990 census, all water blocks in a block group were assigned to block X99 (often followed by an alphabetic suffix), with the first digit based on the block group in which the water body was located. Block numbers for water bodies appear only in the TIGER/Line® files.Q. Block numbers are completely different from the block numbers I saw for the precensus activities in which we participated.
A. For precensus operations and for taking the census, the U.S. Census Bureau assigned a single sequence of numbers to the blocks within each county or statistically equivalent entity. These block numbers used either 4 or 5 digits, depending on the number of blocks in each entity, and could have included an alphabetic suffix. The Census Bureau called these collection block numbers, and all materials for precensus operations and programs that involved the public noted that the Census Bureau would be changing the block numbers for data tabulation (tabulation block numbers). For data presentation, Census 2000 uses only 4-digit block numbers, which are unique within census tract, and thus are likely to duplicate within a county or statistically equivalent entity; also, tabulation block numbers do not have suffixes. Block numbers for the precensus and census activities ignored many legal boundaries, whereas for data tabulation, the Census Bureau held every tabulation area boundary as a block boundary.Q. Data for crews of vessels used to be available for blocks that were assigned a unique "Z" suffix. Where do I find these data now?
A. For Census 2000, the crews-of-vessels population is assigned to the land census tract and census block that contains the facility, dock, or pier related to the ship, or that adjoins the related water body. To simplify geographic display and user understanding, the U.S. Census Bureau decided that a separate geographic designation was neither necessary nor desirable. In the data, the Census Bureau highlights the fact that a block contains shipboard population by including a special group quarters code for that population. The Z suffix is not used for Census 2000.Note: If necessary, refer to the answer regarding census tracts for crews of vessels.
Q. I notice that Census 2000 provides data for urban clusters. What are these?
A. For recent censuses, the U.S. Census Bureau defined urban as including all population and territory in urbanized areas, which are densely settled areas containing at least 50,000 people, and in other places with a population of 2,500 or more (but excluding the portion of a few incorporated places that contained a significant amount of sparsely settled territory). To provide better data for the nation's urban and rural populations, the Census Bureau decided it was necessary to establish a geographic entity that better supplemented the urbanized areas. Thus, for Census 2000, it established urban clusters, which are densely settled areas with a population of 2,500 to 49,999.3 The Census Bureau also made some refinements to the criteria for delineating urbanized areas for Census 2000.Note: The new definition of urban and related terminology, and the criteria for designating and delineating urban areas, were published in the Federal Register on March 15, 2002. The Federal Register Notice is accessible from the Census Bureau's Urban and Rural Classification Web page.
Q. I notice that many more places are partly urban and partly rural.
A. Delineation of urbanized areas and urban clusters is now based strictly on aggregations of block groups and census blocks, and therefore do not take into consideration the boundaries of legal and statistical entities as the urbanized areas did for the 1990 census. Census 2000 refers to places that are partly urban and partly rural as extended places; this replaces the previous term, extended cities, because a census designated place (as well as any incorporated place) can now be partly urban and partly rural.Q. What is the effect of the change in the urban definition?
A. Many places - both incorporated places and census designated places - will now be split between urban and rural components. The U.S. Census Bureau estimates that the changes in the criteria may classify as urban as many as an additional 3 percent of the population (about 5 million people), but 7 percent less area (about 6,600 square miles).Q. I notice that Census 2000 provides data for state legislative districts. What are these?
A. Presentation of data for state legislative districts (SLDs) is new for Census 2000. The U.S. Census Bureau offered to provide states with data for the geographic areas represented by senators, representatives, delegates, etc., in their state legislatures. State officials were given the opportunity to identify their legislative districts by providing boundary and code information for both their senate and house chambers - that is, State Legislative District (Upper Chamber) and State Legislative District (Lower Chamber) - as part of the Redistricting Data Program for Census 2000. Participation was voluntary, and ten states (Arkansas, California, Florida, Hawaii, Kentucky, Maine, Maryland, Minnesota, Montana, and Texas) chose not to participate; New Hampshire chose to provide information only for its house of representatives, and Nebraska, which has a unicameral legislature, has data only for an "upper chamber."Q. The Office of Management and Budget issued new standards for metropolitan-type areas. Do the data issued for Census 2000 reflect those standards?
A. The Office of Management and Budget (OMB) announced revised standards for metropolitan statistical areas, and a new type of entity called a micropolitan statistical area, in the Federal Register on December 27, 2000. However, the OMB will not identify the entities that are based on the new standards and Census 2000 data until mid-2003. The Census 2000 data products present information for the metropolitan areas and central cities announced by the OMB on June 30, 1999, and therefore are in effect on Census Day, April 1, 2000; these entities reflect the 1990 metropolitan area standards.Note: Both the new and current standards are available on the following Web site: http://www.census.gov/population/www/estimates/masrp.html.
Q. I notice that Census 2000 provides data for urban growth areas. What are these?
A. The state of Oregon established limits to control new urban development around every incorporated place or a combination of incorporated places. The U.S. Census Bureau agreed to recognize these "urban growth boundaries" so that it could provide Census 2000 data for the areas within these boundaries. State and local officials identified the boundaries for the Census Bureau. Census 2000 is the first time that the Census Bureau provided data for these entities.Q. I notice that Census 2000 provides data for ZIP Code tabulation areas, or ZCTAs.TM Are these the same as the U.S. Postal Service's ZIP Codes® and/or the ZIP Codes for which the 1990 census provided data?
A. ZIP Codes are established by the U.S. Postal Service (USPS) to expedite the delivery of mail. While it is common practice to refer to "ZIP Code areas," most ZIP Codes do not cover an easily definable area, nor do they have specific boundaries. Nevertheless, because data users want decennial census data for ZIP Codes, the U.S. Census Bureau first provided such data in conjunction with the 1990 census. However, rather than using census addresses to delineate ZIP Codes for that census, the Census Bureau purchased a file providing ZIP Code-to-census block comparability from a commercial firm; this file enabled the Census Bureau to tabulate data for areas that approximated ZIP Codes.For Census 2000, the Census Bureau developed software that enabled it to assign, in an automated fashion, clusters of census blocks whose mailing addresses shared the same predominant ZIP Code, based on information stored in its own address file. The automated clustering was followed by a manual review and cleanup. However, because this clustering of blocks again only approximates ZIP Code delivery areas, the Census Bureau calls them ZIP Code tabulation areas, or ZCTAs. Because the approach for Census 2000 is essentially similar to the one used in the 1990 census - that is, ZIP Code data are based on tabulating data based on one or more census blocks - the Census Bureau estimates that performing the ZCTA identification, of itself, does not seriously affect the validity or comparability of the data. However, the coverage for the same ZIP-numbered area could be different because the USPS changed the coverage of many ZIP Codes and added new ZIP Codes since 1990. In addition, ZCTAs recognize ZIP Codes that are dedicated entirely to post office boxes in rural areas.
Note: The term "ZCTA" is a trademark of the U.S. Census Bureau. The term "ZIP Code" is a registered trademark of the U.S. Postal Service.
Q. I notice that public use microdata areas are somewhat different for Census 2000.
A. There are several changes for public use microdata areas (PUMAs) from the 1990 census:1 A "land base" refers to a legally defined reservation and/or off-reservation trust land.
2 Federal Information Processing Standards (FIPS) codes are sets of codes issued by the federal government's National Institute of Standards and Technology (NIST) for the purpose of ensuring uniform identification of entities for computer processing throughout all federal government programs and agencies. Further information about the standards and codes can be found on the NIST's Web site at http://www.itl.nist.gov/fipspubs.
Alaska Native Regional Corporation (ANRC) - A corporate entity established to conduct both business and nonprofit affairs of Alaska Natives, pursuant to the Alaska Native Claims Settlement Act of 1972 (Public Law 92-203, as amended). Twelve ANRCs are legally bounded geographic entities that cover Alaska, except for the Annette Islands Reserve (an American Indian reservation). A thirteenth ANRC represents Alaska Natives who do not live in Alaska and do not identify with any of the 12 corporations; the U.S. Census Bureau does not present data for this ANRC.
Alaska Native village (ANV) - A local governmental unit in Alaska that constitutes an association, band, clan, community, group, tribe, or village, recognized pursuant to the Alaska Native Claims Settlement Act of 1972 (Public Law 92-203, as amended). ANVs do not have clearly defined boundaries that are easily locatable, and they often include many square miles of land used by Alaska Natives for hunting and fishing, so the U.S. Census Bureau works with officials of the Alaska Native villages and Alaska Native Regional Corporations to delineate Alaska Native village statistical areas for data presentation purposes.
Alaska Native village statistical area (ANVSA) - A statistical entity that represents the settled portion of an Alaska Native village for data presentation purposes.
American Indian off-reservation trust land - The United States holds title for specific area in trust for the benefit of an American Indian tribe (tribal trust land) or for an individual American Indian (individual trust land). Although trust land may be located on or off a reservation, the U.S. Census Bureau recognizes and tabulates data only for off-reservation trust land. Census data always associate off-reservation trust land with a specific federally recognized reservation and/or tribal government. See American Indian reservation, American Indian trust land.
American Indian reservation - A federal American Indian reservation is an area that has been set aside by the United States for the use of one or more federally recognized American Indian tribes. Together with off-reservation trust land, a reservation covers territory over which one or more tribes have primary governmental authority. The boundary of a federal reservation is defined by tribal treaty, agreement, executive or secretarial order, federal statute, or judicial determination. A state American Indian reservation is an area that a state government has allocated to a tribe recognized by that state, but not by the federal government. American Indian reservations are known as colonies, communities, Indian communities, Indian villages, pueblos, rancherias, ranches, reservations, reserves, and villages. See American Indian off-reservation trust land, American Indian tribal subdivision, American Indian trust land, joint use area.
American Indian tribal subdivision - A legal subdivision of a federally recognized American Indian reservation, off-reservation trust land, or Oklahoma tribal statistical area. These entities are internal units of self-government or administration that serve social, cultural, and/or economic purposes for American Indians living on a reservation, off-reservation trust land, or Oklahoma tribal statistical area. Tribal subdivisions are known as areas, chapters, communities, districts, and segments. The U.S. Census Bureau previously provided unpublished data for these entities for the 1980 census, which referred to them as American Indian subreservation areas.
American Indian trust land - An area for which the United States holds title in trust for the benefit of an American Indian tribe (tribal trust land) or for an individual American Indian (individual trust land). Trust land may be located on or off a reservation; however, the U.S. Census Bureau recognizes and tabulates data only for off-reservation trust land. See American Indian off-reservation trust land, Hawaiian home land.
barrio, barrio-pueblo - The U.S. Census Bureau recognizes barrios and barrios-pueblo as the primary legal divisions of municipios. These entities are similar to the minor civil divisions (MCDs) used for reporting decennial census data in 28 states of the United States. Subbarrios in 23 municipios are the primary legal subdivisions of the barrios-pueblo and some barrios. The Census Bureau presents the same types of Census 2000 data for these "sub-MCDs" as it does for the barrios and barrios-pueblo. Each barrio, barrio-pueblo, and subbarrio is assigned a five-digit Federal Information Processing Standards (FIPS) code in alphabetical order within Puerto Rico. See subbarrio.
block - See census block.
block boundary - The features that delimit a census block. The features may be visible (a street, road, stream, shoreline, power line, etc.) or invisible (a county line, city limit, property line, imaginary extension of a street or road, etc.). Generally, the boundary of a census block must include at least one addressable feature; that is, a street or road. For data tabulation, the boundary of every legal and statistical entity recognized in the U.S. Census Bureau's standard data tabulations is a block boundary.
block group (BG) - A statistical subdivision of a census tract (or, prior to Census 2000, a block numbering area). A BG consists of all tabulation blocks whose numbers begin with the same digit in a census tract. For example, for Census 2000, BG 3 within a census tract includes all blocks numbered from 3000 to 3999. (A few BGs consist of a single block.) BGs generally contain between 300 and 3,000 people, with an optimum size of 1,500 people. The BG is the lowest-level geographic entity for which the U.S. Census Bureau tabulates sample data from a decennial census. See tribal block group.
block number - A number assigned to each census block.
block numbering area (BNA) - Prior to Census 2000, a statistical subdivision of a county or statistically equivalent entity, delineated by a state government agency or a U.S. Census Bureau regional census center for the purpose of grouping and numbering census blocks in counties that did not have census tracts. BNAs were discontinued for Census 2000; they were replaced by census tracts in every county and statistically equivalent entity.
borough - A legally established geographic entity in Alaska, which the Census Bureau treats as statistically equivalent to a county in other states; a minor civil division in each of the five counties that comprise New York city; a type of incorporated place in Connecticut, New Jersey, and Pennsylvania.
census area - A statistical entity that serves as the equivalent of a county in Alaska. Census areas are delineated cooperatively by the state of Alaska and the U.S. Census Bureau for the purpose of presenting census data for the portion of Alaska not within an organized borough, city and borough, or municipality.
census block - A geographic area bounded by visible and/or invisible features shown on a map prepared by the U.S. Census Bureau. A block is the smallest geographic entity for which the Census Bureau tabulates decennial census data. See block boundary, block number.
Census Bureau map - Any map, in electronic or paper form, produced by the U.S. Census Bureau. Such a map usually displays the boundaries and names and/or codes of the geographic entities that the Census Bureau uses to take a census or survey, or for which the Census Bureau tabulates data, and may include both visible and invisible features, feature names, and other information appropriate to the purpose for which the map was prepared. Some Census Bureau maps display statistical data in various thematic forms. Every Census Bureau map displays a credit note showing that it was produced by the U.S. Census Bureau.
census county division (CCD) - A statistical subdivision of a county, established and delineated cooperatively by the U.S. Census Bureau and state, local, and tribal officials for data presentation purposes. CCDs have been established in 21 states that do not have minor civil divisions suitable for data presentation; that is, minor civil divisions have not been legally established, do not have governmental or administrative purposes, have boundaries that are ambiguous or change frequently, and/or generally are not well known to the public.
census designated place (CDP) - A geographic entity that serves as the statistical counterpart of an incorporated place for the purpose of presenting census data for an area with a concentration of population, housing, and commercial structures that is identifiable by name, but is not within an incorporated place. CDPs usually are delineated cooperatively with state, Puerto Rico, Island Area, local, and tribal officials based on U.S. Census Bureau guidelines. For Census 2000, for the first time, CDPs did not need to meet a minimum population threshold to qualify for the tabulation of census data. See place. Note: A CDP in Puerto Rico is called a comunidad or zona urbana.
census division - A grouping of states and the District of Columbia, established by the U.S. Census Bureau for the presentation of census data. The nine divisions represent areas that were relatively homogeneous when they were established in 1910. The divisions are subdivisions of the four census regions.
census geography - A collective term referring to the geographic entities used by the U.S. Census Bureau in its data collection and tabulation operations, including their relationships to one another. See geographic hierarchy, tabulation geography.
census map - See Census Bureau map.
census region - A grouping of states and the District of Columbia, established by the U.S. Census Bureau for the presentation of census data. The four regions represent areas that were relatively homogeneous when they were established in 1910 and revised in 1950. Each region is divided into two or three census divisions.
census subarea - A statistical subdivision of a borough, census area, or other entity that is the statistical equivalent of a county in Alaska. A census subarea is similar to a census county division in other states. Census subareas are delineated cooperatively by the state of Alaska and the U.S. Census Bureau.
census tract - A small, relatively permanent statistical subdivision of a county or statistically equivalent entity, delineated for data presentation purposes by a local group of census data users or the geographic staff of a regional census center in accordance with U.S. Census Bureau guidelines. Designed to be relatively homogeneous units with respect to population characteristics, economic status, and living conditions at the time they are established, census tracts generally contain between 1,000 and 8,000 people, with an optimum size of 4,000 people. Census tract boundaries are delineated with the intention of being stable over many decades, so they generally follow relatively permanent visible features. However, they may follow governmental unit boundaries and other invisible features in some instances; the boundary of a state or county (or statistically equivalent entity) is always a census tract boundary. When data are provided for American Indian entities, the boundary of a federally recognized American Indian reservation and off-reservation trust land is always the boundary of a tribal census tract. See block numbering area, tribal census tract.
census tract number - A 4-digit number, which may be followed by a 2-digit decimal suffix, used to identify a census tract uniquely within a county or statistically equivalent entity. For Census 2000, census tract numbers range from 0001 to 9999, with 9400 to 9499 reserved for census tracts related to federally recognized American Indian reservations and off-reservation trust land - primarily reservations and trust land that cross county lines. Leading zeros and a suffix of ".00" usually do not appear on maps prepared by the U.S. Census Bureau, and are not commonly used when referring to a particular census tract. The number "0000" in computer-readable files identifies a census tract delineated to provide complete coverage of water area in territorial seas and the Great Lakes.
central city - In a metropolitan area, the largest place and, in some areas, one or more additional places that meet official standards. A few primary metropolitan statistical areas do not have a central city.
central place - In an urbanized area or urban cluster, the largest incorporated place, or census designated place in some cases, and one or more additional places that meet specific criteria. For an urbanized area or urban cluster that does not contain an incorporated or census designated place, there is no central place (the title of the urbanized area or urban cluster uses the name of a minor civil division, or a local place name recognized by the Board on Geographic Names and recorded by the U.S. Geological Survey, but the name does not represent a central place).
city - A type of incorporated place in all states and the District of Columbia. In agreement with the state of Hawaii, the U.S. Census Bureau does not recognize the city of Honolulu for presentation of census data. In Virginia, all cities are not part of any county, and so the Census Bureau treats them as equivalent to a county for data presentation purposes, as well as treating them as places; there also is one such independent city in each of three states: Maryland, Missouri, and Nevada. In 23 states and the District of Columbia, some or all cities are not part of any minor civil division, in which case the Census Bureau treats them as county subdivisions as well as places for data presentation purposes.
city and borough - A legally established geographic entity in Alaska, which the U.S. Census Bureau treats as the statistical equivalent of a county in other states; also, a type of incorporated place in Alaska. This designation is new for Census 2000.
code - See geographic code.
collection block - The smallest area that the U.S. Census Bureau used to collect information for the decennial census. A collection block may be split by the boundary of any legal or statistical entity later recognized by the Census Bureau for census data presentation. Thus, if a collection block is split by one or more legal and/or statistical boundaries, each portion will be a separate tabulation block; if a collection block is not split, the same area may be a tabulation block. See block number, census block, tabulation block.
comunidad - A census designated place in Puerto Rico that is not related to a municipio's seat of government. See census designated place, zona urbana.
congressional district (CD) - One of the 435 areas from which people are elected to the U.S. House of Representatives. The CDs for which Census 2000 first provides data are those for the 106th Congress.
consolidated city - The U.S. Census Bureau refers to a governmental unit for which the functions of an incorporated place and its county or minor civil division have merged as a consolidated government. If one or more other incorporated places continue to function as separate governmental units even though they are part of a consolidated government, the Census Bureau refers to the primary incorporated place as a consolidated city.
consolidated metropolitan statistical area (CMSA) - A geographic entity designated by the federal Office of Management and Budget (OMB) for use by federal statistical agencies. An area becomes a consolidated metropolitan statistical area (CMSA) if it qualifies as a metropolitan area (MA), has a census population of 1,000,000 or more, has component parts that qualify as primary metropolitan statistical areas (PMSAs) based on official standards, and local opinion favors the designation. CMSAs consist of whole counties except in New England, where they consist of county subdivisions (primarily cities and towns). See central city, metropolitan area, metropolitan statistical area, New England County Metropolitan Area, primary metropolitan statistical area, statistical entity.
county - The primary legal division of every state except Alaska and Louisiana. A number of geographic entities are not legally designated as a county, but are recognized by the U.S. Census Bureau as equivalent to a county for data presentation purposes. These include the boroughs, city and boroughs, municipality, and census areas in Alaska; parishes in Louisiana; and cities that are independent of any county in Maryland, Missouri, Nevada, and Virginia. They also include the municipios in Puerto Rico, districts and islands in American Samoa, municipalities in the Northern Mariana Islands, and islands in the Virgin Islands of the United States. Because they contain no primary legal divisions, the Census Bureau treats the District of Columbia and Guam each as equivalent to a county (as well as equivalent to a state) for data presentation purposes. In American Samoa, a county is a minor civil division.
county subdivision - The primary legal or statistical division of a county or statistically equivalent entity. See census county division, census subarea, minor civil division, unorganized territory.
division (census geographic) - See census division.
extended city - See extended place.
extended place - A place that contains both urban and rural territory; i.e., an incorporated place or census designated place that is partially within and partially outside of an urbanized area or urban cluster. The term is first used for Census 2000. Previously referred to as an extended city, which applied only to incorporated places, subject to very specific criteria.
geographic code - A code, consisting of one or more alphanumeric or special-text characters, used to identify a geographic entity. Every geographic entity recognized by the Census Bureau is assigned one or more geographic codes. Also referred to as a geocode.
geographic entity - A spatial unit of any type, legal or statistical, such as the United States, a state, county, county subdivision, place, census tract, block group, or census block. See census geography, legal entity, statistical entity.
geographic hierarchy - A geographic presentation that shows the geographic entities in a superior/subordinate structure. In this system of relationships among geographic entities, each entity (except the smallest one) is subdivided into lower-order units that in turn may be subdivided further. For example, states are subdivided into counties, which are subdivided into both county subdivisions and census tracts. The Census Bureau uses three sets of hierarchies: one is based on states and counties; another on American Indian area, Alaska Native areas, and Hawaiian home lands; and a third on metropolitan or urban areas. See census geography, tabulation geography.
governmental unit (GU) - A geographic entity established by legal action for the purpose of implementing specified general- or special-purpose governmental functions. Most GUs have legally established boundaries and names, and have officials (usually elected) who have the power to carry out legally prescribed functions, provide services for the residents of the GU, and raise revenues. Some GUs do not have officials or do not implement the powers that the law entitles them to; the U.S. Census Bureau refers to these entities as inactive governmental units.
Hawaiian home land (HHL) - An area held in trust for the benefit of native Hawaiians by the state of Hawaii, pursuant to the Hawaiian Homes Commission Act of 1920, as amended. Hawaiian home lands are a new type of geographic entity for Census 2000.
incorporated place - A type of governmental unit, incorporated under state law as a city, town (except in New England, New York, and Wisconsin), borough (except in Alaska and New York), or village, generally to provide a wide array of specific governmental services for a concentration of people within legally prescribed boundaries. New for Census 2000 are "city and borough" and "municipality," which serve as both place- and county-level entities in Alaska. A few incorporated places do not have a legal description. See consolidated city, governmental unit, independent city, independent place, place.
independent city - An incorporated place that is independent of - i.e., not part of - any county. All incorporated places classified as cities in Virginia are independent cities, as are Baltimore, MD; St. Louis, MO; and Carson City, NV. The U.S. Census Bureau treats an independent city as equivalent to a county and, where appropriate, as a county subdivision and as an incorporated place for data presentation purposes.
independent place - In a state in which the Census Bureau recognizes minor civil divisions (MCDs), an incorporated place that is not legally part of any MCD. The Census Bureau treats an independent place as equivalent to a county subdivision and as an incorporated place for data presentation purposes. Independent places exist in 23 states and the District of Columbia.
Indian reservation - See American Indian reservation.
Island Areas - For Census 2000, several legal entities under the jurisdiction of the United States: American Samoa, Guam, the Commonwealth of the Northern Mariana Islands, and the Virgin Islands of the United States. The U.S. Census Bureau treats these entities as equivalent to states for data presentation purposes. The term also includes several small islands in the Caribbean Sea and Pacific Ocean; the Census Bureau provides only population counts for these "U.S. Minor Outlying Islands," based on records obtained from the government agency that administers each island (most are unpopulated). Formerly referred to as the Outlying Areas.
joint use area - Territory that is administered, claimed, and/or used by two or more American Indian tribes. It may consist of an overlap of territory of adjoining American Indian reservations or Oklahoma tribal statistical areas, or off-reservation trust land for one tribe that is located within the reservation of another tribe. Such territory was referred to as joint area for the 1990 census.
legal entity - A geographic entity whose origin, boundary, name, and description result from charters, laws, treaties, or other administrative or governmental action, including the United States; the 50 states, the District of Columbia, Puerto Rico, and the Island Areas; counties and statistically equivalent legal entities; minor civil divisions; incorporated places, including consolidated cities; American Indian reservations, off-reservation trust land, and tribal subdivisions; Alaska Native Regional Corporations; Hawaiian home lands; congressional districts; state legislative districts; most voting districts; and school districts. Some legal entities, such as Hawaiian home lands, congressional districts, and voting districts, have no governmental officials or powers, but serve only as nonfunctioning administrative entities. The legal entities and their boundaries that the U.S. Census Bureau recognizes for Census 2000 are those that existed on January 1, 2000. See governmental unit, statistical entity.
metropolitan area (MA) - A core areas with a large population nucleus, together with adjacent communities that have a high degree of economic and social integration with that core. (Some MAs are defined around two or more nuclei.) MAs are designated by the federal Office of Management and Budget (OMB) in terms of one or more counties or, in New England, county subdivisions (primarily cities and towns). The OMB defines and designates metropolitan areas based on a set of official standards that are published in the Federal Register. "Metropolitan area" is a collective term established by the OMB in 1990 to refer to metropolitan statistical areas (MSAs), consolidated metropolitan statistical areas (CMSAs), primary metropolitan statistical areas (PMSAs), and New England County Metropolitan Areas (NECMAs).
Note: In 2003, a new set of standards will go into effect, creating several new types of statistical entities and renaming others, and discontinuing the term "metropolitan area."
metropolitan statistical area (MSA) - A geographic entity designated by the federal Office of Management and Budget for use by federal statistical agencies. A metropolitan statistical area (MSA) is a metropolitan area (MA) that is not closely associated with another MA. An MSA consists of one or more counties, except in New England, where MSAs are defined in terms of county subdivisions (primarily cities and towns). See central city, consolidated metropolitan statistical area, metropolitan area, New England County Metropolitan Area, primary metropolitan statistical area, statistical entity.
minor civil division (MCD) - A type of governmental unit that is the primary governmental or administrative division of a county or statistically equivalent entity in many states and statistically equivalent entities. MCDs are identified by a variety of terms, such as township, town (in eight states), or district. The U.S. Census Bureau recognizes MCDs in 28 states, the District of Columbia, Puerto Rico, and the Island Areas. In 20 states and American Samoa, all or many MCDs are active general-purpose governmental units. Many MCDs are not general-purpose governmental units, and therefore do not have elected officials to carry out legal functions; instead, they serve as nonfunctioning administrative entities. See county subdivision, governmental unit, independent place, legal entity.
municipality - A legally established entity in Alaska and the Northern Mariana Islands. The U.S. Census Bureau treats this entity as the statistical equivalent of a county, and the Census Bureau also treats the municipality (Anchorage) in Alaska as an incorporated place. This designation in Alaska is new for Census 2000.
municipio - A governmental unit that is the primary legal division of Puerto Rico. The U.S. Census Bureau treats a municipio as equivalent to a county in the United States for data presentation purposes.
New England County Metropolitan Area (NECMA) - A county-based area designated by the federal Office of Management and Budget to provide an alternative to the county subdivision-based metropolitan statistical areas and consolidated metropolitan statistical areas in New England. See central city, metropolitan area, statistical entity.
off-reservation trust land - See American Indian off-reservation trust land.
Oklahoma tribal statistical area (OTSA) - A statistical entity identified and delineated by the U.S. Census Bureau in consultation with federally recognized American Indian tribes in Oklahoma that once had a reservation in that state. An OTSA encompasses an area that conforms to a tribe's reservation that was dissolved preceding the establishment of Oklahoma as a state in 1907. For some OTSAs, neighboring tribes agreed to modify the boundary for data presentation purposes. Referred to as a tribal jurisdiction statistical area (TJSA) for the 1990 census and by a single all-encompassing entity called the "Historic Areas of Oklahoma (excluding urbanized areas)" for the 1980 census.
Outlying Areas - See Island Areas.
parish - A governmental unit that is the primary legal subdivision of Louisiana. The U.S. Census Bureau treats a parish as equivalent to a county in other states for data presentation purposes.
place - A concentration of population either legally bounded as an incorporated place, or delineated for statistical purposes as a census designated place (in Puerto Rico, a comunidad or zona urbana). See census designated place, consolidated city, incorporated place, independent city, independent place.
primary metropolitan statistical area (PMSA) - A geographic entity designated by the federal Office of Management and Budget for use by federal statistical agencies. If an area that qualifies as a metropolitan area (MA) has a census population of one million or more, two or more primary metropolitan statistical areas (PMSAs) may be defined within it if they meet official standards and local opinion favors the designation. When PMSAs are established within an MA, that MA is designated a consolidated metropolitan statistical area (CMSA). See central city, consolidated metropolitan statistical area, metropolitan area, statistical entity.
pseudo-voting district (pseudo-VTD) - An area for which the U.S. Census Bureau reports voting district (VTD) data, even though the boundary of the actual voting district was adjusted by the reviewing officials, for purposes of data presentation, so that it no longer matches the legally established boundary. See voting district.
public use microdata area (PUMA) - A geographic entity for which the U.S. Census Bureau provides specially selected extracts of raw information from a small sample of long-form census records that are screened to protect confidentiality of census records. The extract files are referred to as public use microdata samples (PUMS). Public use microdata areas (PUMAs), which must have a minimum census population of 100,000 and cannot cross a state line, receive a 5-percent sample of the long-form records; these records are presented in state files. These PUMAs are aggregated into super-PUMAs, which must have a minimum census population of 400,000 and receive a 1-percent sample in a national file. The Census Bureau provided a 10-percent sample file each for Guam and the Virgin Islands of the United States. Data users can use these files to create their own statistical tabulations and data summaries.
region (census geographic) - See census region.
rural - All territory, population, and housing units located outside of urbanized areas and urban clusters. See urban.
school district - A geographic entity within which state, county, or local officials or the U.S. Department of Defense provides public educational services for an area's residents. The U.S. Census Bureau provides data for three types of school districts: elementary, secondary, and unified.
state - A primary governmental division of the United States. The U.S. Census Bureau treats the District of Columbia as the equivalent of a state for data presentation purposes. It also treats a number of entities that are not legal divisions of the United States as the equivalent of states for data presentation purposes: Puerto Rico and the Island Areas.
state designated American Indian statistical area (SDAISA) - A statistical entity delineated for an American Indian tribe that does not have a land base (reservation) and is recognized as a tribe by a state government, but not the federal government. State designated American Indian statistical areas (SDAISAs) are identified and delineated for the U.S. Census Bureau by a state liaison identified by the governor's office. A SDAISA generally encompasses a compact and contiguous area that contains a concentration of people who identify with a state recognized American Indian tribe and in which there is structured or organized tribal activity. A SDAISA may not be located in more than one state unless the tribe is recognized by both states, and it may not include area within an American Indian reservation, off-reservation trust land, Oklahoma tribal statistical area, tribal designated statistical area, or Alaska Native village statistical area. SDAISAs were included with tribal designated statistical areas for the 1990 census; this designation is new for Census 2000.
state legislative district (SLD) - The area represented by a member of the upper or lower chamber of a state legislature (or, for Nebraska, the unicameral legislature).
statistical entity - A geographic entity that is specially defined and delineated so that the U.S. Census Bureau may tabulate data for it. Statistical entities include census areas (in Alaska), census county divisions, census subareas (in Alaska), unorganized territories, census designated places, Oklahoma tribal statistical areas, tribal designated statistical areas, state designated American Indian statistical areas, Alaska Native village statistical areas, metropolitan areas, urban areas, census tracts, block groups, and census blocks. Designation as a statistical entity neither conveys nor confers legal ownership, entitlement, or jurisdictional authority. See legal entity.
subbarrio - A legal subdivision of a barrio or barrio-pueblo (minor civil division) in 23 municipios in Puerto Rico. (There is no geographic entity in the United States equivalent to a subbarrio.) Census 2000 provides the same types of data for subbarrios as it does for barrios and barrios-pueblo. Each subbarrio is assigned a five-digit Federal Information Processing Standards (FIPS) code in alphabetical order within Puerto Rico. See barrio, barrio-pueblo; sub-MCD.
sub-MCD - A legal subdivision of a minor civil division (MCD). For Census 2000, only Puerto Rico has sub-MCDs (subbarrios).
super-PUMA - See public use microdata area.
tabulation block - The smallest area for which the U.S. Census Bureau provides decennial census data. A tabulation block cannot be split by the boundary of any legal or statistical entity recognized by the Census Bureau for census data presentation. See block number, census block.
tabulation geography - The geographic entities for which the U.S. Census Bureau tabulates and presents data. See geographic entity, geographic hierarchy.
tract - See census tract.
traffic analysis zone (TAZ) - A statistical entity delineated by state and/or local transportation officials for tabulating traffic-related data - especially journey-to-work and place-of-work statistics - from a decennial census. A TAZ usually consists of one or more census blocks, block groups, or census tracts.
tribal block group - A block group within a tribal census tract. Where a census tract numbered in the 9400 series crosses a county line, a tribal block group may be located on both sides of that boundary. See block group, tribal census tract.
tribal census tract - A census tract within a federally recognized American Indian reservation and/or off-reservation trust land. Some of these census tracts are numbered in the 9400 series, primarily if they cross a county line. See census tract, tribal block group.
tribal designated statistical area (TDSA) - A statistical entity delineated for the U.S. Census Bureau by a federally recognized American Indian tribe that does not have a land base (a federally recognized reservation or off-reservation trust land). A TDSA generally encompasses a compact and contiguous area that contains a concentration of people who identify with a federally recognized American Indian tribe and in which there is structured or organized tribal activity. A TDSA may not include area within an American Indian reservation, off-reservation trust land, Oklahoma tribal statistical area, state designated American Indian statistical area, or Alaska Native village statistical area. For the 1990 census, it could not cross a state line, but it may do so for Census 2000. For the 1990 census, TDSAs included state-recognized tribes without a land base; these are now called state designated American Indian statistical areas.
tribal jurisdiction statistical area (TJSA) - See Oklahoma tribal statistical area.
tribal subdivision - See American Indian tribal subdivision.
trust land - See American Indian trust land.
United States - The 50 states and the District of Columbia.
unorganized territory (UT) - In a state in which the U.S. Census Bureau provides data for minor civil divisions (MCDs), the portion of a county that is not included in a legally established MCD or in an incorporated place that is independent of an MCD. For data presentation purposes, the Census Bureau recognizes such area as one or more separate county subdivisions, each designated as an unorganized territory. For Census 2000, ten states contain one or more UTs.
urban - All territory, population, and housing units located within urbanized areas and urban clusters. See rural, urban area.
urban area - A generic term that refers to both urbanized areas and urban clusters. This terminology is new for Census 2000.
urban cluster (UC) - A densely settled area that has a census population of 2,500 to 49,999. A UC generally consists of a geographic core of block groups or blocks that have a population density of at least 1,000 people per square mile, and adjacent block groups and blocks with at least 500 people per square mile. A UC consists of all or part of one or more incorporated places and/or census designated places; such a place(s) together with adjacent territory; or territory outside of any place. See central place, extended place, urban, urbanized area.
Note: Any urban area delineated in Guam is classified as an urban cluster regardless of its population size.
urban growth area (UGA) - In Oregon, an "urban growth boundary" is delineated around each incorporated place or a group of incorporated places by state and local officials, and subsequently confirmed in state law, to control urban development. The U.S. Census Bureau refers to the resulting geographic entities as "urban growth areas" (UGAs). UGAs are new for Census 2000. ("Urban growth boundary" is a legal term; "urban growth area" is a census term.)
urbanized area (UA) - A densely settled area that has a census population of at least 50,000. A UA generally consists of a geographic core of block groups or blocks that have a population density of at least 1,000 people per square mile, and adjacent block groups and blocks with at least 500 people per square mile. A UA consists of all or part of one or more incorporated places and/or census designated places, and may include additional territory outside of any place. See central place, extended place, urban, urban cluster.
voting district (VTD) - The generic name for a geographic entity - such as an election district, precinct, or ward - established by state, local, and tribal governments for the purpose of conducting elections. Some reviewing officials adjusted the boundaries of the voting districts (VTDs) they submitted to conform to census block boundaries for data presentation purposes, and therefore a VTD for which Census 2000 provides data might not exactly represent the legal entity; the U.S. Census Bureau refers to such VTDs as pseudo-voting districts (pseudo-VTDs). Such VTDs, as well as any territory for which state officials did not specify a status, are identified by a "P" in the VTD indicator field of the PL data file.
ZIP Code area - The addresses served by a 5-digit ZIP Codea - established by the U.S. Postal Service to expedite the delivery of mail. Most ZIP Codes do not have specific boundaries, and their implied boundaries do not necessarily follow clearly identifiable visible or invisible map features; also, the carrier routes for one ZIP Code may intertwine with those of one or more other ZIP Codes, and therefore this area is more conceptual than geographic. See ZIP Code tabulation area.
ZIP Code tabulation area (ZCTAa) - A statistical entity developed by the U.S. Census Bureau to approximate the delivery area for a U.S. Postal Service 5-digit or 3-digit ZIP Codea in the United States and Puerto Rico. A ZCTA is an aggregation of census blocks that have the same predominant ZIP Code associated with the mailing addresses in the Census Bureau's Master Address File. Thus, the Postal Service's delivery areas have been adjusted to encompass whole census blocks so that the Census Bureau can tabulate census data for the ZCTAs. For areas larger than 25 square miles for which the Census Bureau's Master Address File contained no addresses with ZIP Codes, the Census Bureau used the first 3 digits of the ZIP Code(s) that serve the area or nearby areas. For the dress rehearsal data, there are two blank spaces after such 3-digit codes; for Census 2000, there is a suffix of "XX." A water feature that could not logically be assigned to a specific ZCTA is assigned a 3-digit code followed by "HH" to indicate that the water feature could not be assigned meaningfully to any adjacent land ZCTA. ZCTAs do not include all ZIP Codes used for mail delivery. The Census Bureau first created ZCTAs for the Census 2000 dress rehearsal census. See ZIP Code area.
zona urbana - In Puerto Rico, a census designated place consisting of the municipio seat of government and the adjacent built-up area. A zona urbana cannot extend across its municipio's boundary. See census designated place, comunidad.
a Note that "ZCTA" is a trademark of the U.S. Census Bureau, and "ZIP Code" is a registered trademark of the U.S. Postal Service.
