Current Lists of Metropolitan and Micropolitan Statistical Areas and Definitions

A metropolitan or micropolitan statistical area's geographic delineation, or list of geographic components at a particular point in time, is referred to as its "definition." Metropolitan and micropolitan statistical areas are defined by the U.S. Office of Management and Budget (OMB) and are the result of the application of published standards to Census Bureau data. The standards for defining the areas are reviewed and revised once every ten years, prior to each decennial census. Generally, the areas are redefined using the most recent set of standards following each decennial census. Between censuses, the definitions are updated annually to reflect the most recent Census Bureau population estimates. Areas based on the 2000 standards and Census 2000 data were defined in June of 2003. The current definitions are as of November 2007.

The files below show definitions of metropolitan and micropolitan statistical areas and related statistical areas defined by OMB since June 2003. Related statistical areas include New England City and Town Areas (NECTAs), which are conceptually similar to metropolitan and micropolitan statistical areas, but are defined using cities and towns instead of counties; Combined Statistical Areas, which are aggregates of adjacent metropolitan or micropolitan statistical areas that are linked by commuting ties; and Combined New England City and Town Areas, which are aggregates of adjacent NECTAs that are linked by commuting ties.

For definitions of metropolitan areas prior to 2003, see the historical definitions page.

Office of Management and Budget (OMB) Bulletins

November 2007 (OMB Bulletin No. 08-01) announcing updates to metropolitan and micropolitan statistical areas as of November 2007, based on Census Bureau’s July 1, 2005 and July 1, 2006 population estimates for cities and towns, and in specified circumstances, local opinion. [PDF]
December 2006 (OMB Bulletin No. 07-01) announcing updates to metropolitan and micropolitan statistical areas as of December 2006, based on the Census Bureau’s July 1, 2004 and July 1, 2005 population estimates for cities and towns, and in specified circumstances, local opinion. [PDF]
December 2005 (OMB Bulletin No. 06-01) announcing updates to metropolitan and micropolitan statistical areas as of December 2005, based on the Census Bureau’s July 1, 2003 and July 1, 2004 population estimates for cities and towns, and in specified circumstances, local opinion. [PDF]
November 2004 (OMB Bulletin No. 05-02) announcing updates to metropolitan and micropolitan statistical areas as of November 2004, based on the Census Bureau’s July 1, 2002 and July 1, 2003 population estimates for cities and towns, and in specified circumstances, local opinion.
December 2003 (OMB Bulletin No. 04-03) announcing updates to metropolitan and micropolitan statistical areas as of December 2003, based on the Census Bureau’s July 1, 2001 and July 1, 2002 population estimates for cities and towns, and in specified circumstances, local opinion.
June 2003 (OMB Bulletin No. 03-04) announcing metropolitan and micropolitan statistical areas as of June 6, 2003, based on application of the 2000 OMB standards to Census 2000 data.

Definition Files

Geographic areas	Date
Metropolitan and micropolitan statistical areas and components
Principal cities of metropolitan and micropolitan statistical areas
Counties with metropolitan and micropolitan statistical area codes
Metropolitan statistical areas and components
Micropolitan statistical areas and components
Combined statistical areas and components
New England city and town areas (NECTAs) and components
Principal cities of New England city and town areas areas
Cities and towns with NECTA and Combined NECTA codes
Metropolitan NECTAs and components
Micropolitan NECTAs and components