The what, why, and how of Census geography. What are the definitions of geographic terms, why are geographic areas defined, and how we define geographic areas. Find reference information such as FIPS and ANSI codes, geographic boundary change notes, significant county boundary changes, and county adjacency information.
Definitions of geographic terms & concepts used in demographic and housing data products
Graphical representations of how geographic areas relate to each other
Detailed explanations of the basic geographic entities from the 1990 Census
Detailed current and historical definitions, delineation information, lists and data files, and links to other products related to selected types of geography
Coordinates for the centers of population from the decennial census, including historical censuses.
Information about selected geographic changes to incorporated places, census designated places, county subdivisions, counties and equivalent areas, and American Indian, Alaska Native, and Native Hawaiian areas
List of counties that share borders
List of current and previous Federal Register notices related to census geography
Lists of geographic entities, such as county, place, and census tracts, with information on name, geographic code, population, housing unit counts, and latitude/longitude of the internal point
Geographic code look-ups and explanation of the various types of geographic codes - FIPS, GNIS, ANSI
Information about the census geography of each state including a brief history of the state's inclusion in the decennial census
Lists of incorporations, mergers, consolidations, and disincorporations submitted to the Census Bureau through the Boundary and Annexation Survey (BAS)
List of interactive mapping applications, other federal government resources, and external national resources.
Land, water and total area measurements for the 50 states, the District of Columbia and Puerto Rico as of the 2010 Census
Listing of county boundary changes by decade that affect at least 200 people or involve a large swap of territory