Overview
The rural-urban commuting area (RUCA) codes classify U.S. census tracts using
measures of population density, urbanization, and daily commuting. The most recent RUCA
codes are based on data from the 2000 decennial census. The classification contains two levels.
Whole numbers (1-10) delineate metropolitan, micropolitan, small town, and rural commuting
areas based on the size and direction of the primary (largest) commuting flows. These 10 codes
are further subdivided to permit stricter or looser delimitation of commuting areas, based on
secondary (second largest) commuting flows. The approach errs in the direction of more codes,
providing flexibility in combining levels to meet varying definitional needs and preferences.
The 1990 codes are similarly defined.
However, the Census Bureau's methods of defining urban cores and
clusters changed between the two censuses. And, census tracts
changed
in number and shapes. The 2000 rural-urban commuting codes are not
directly comparable with the 1990 codes because of these differences.
2000 RUCA Codes
1990 RUCA Codes
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