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How We Map

Cartographers in 1960
Census Bureau cartographers prepare maps for the
1960 census. - View Larger

As the United States expanded and cities grew, there was a need to have accurate maps to locate where people lived and new concepts to classify patterns of settlement. Over the decades new terms such as urban areas, metropolitan areas, census county divisions, and census tracts were added to the list of Census Bureau geographic entities.

With new housing developments and suburbs springing up after World War II, new procedures and mechanisms were needed to help the U.S. Census Bureau map and keep track of annexations and other boundary changes.

As the demand for more accurate and up-to-date statistics grew, so too did the need to represent that information in an easy to understand format such as thematic maps.

Today, the Census Bureau is recognized as an expert in the field of cartography, conducting geographic programs and producing maps that are vital to the nation's politics, commerce, and development. Examples of these programs and cartographic products include:


  • The Boundary and Annexation Survey (BAS). The Boundary and Annexation Survey is an annual survey that collects information about selected legally defined geographic areas. The BAS is used to update information about the legal boundaries and names of all governmental units in the United States. The Census Bureau uses the boundary information collected in the BAS to tabulate data for the decennial and economic censuses, as well as annual estimates and surveys such as the Population Estimates Program and the American Community Survey.
  • Local Update of Census Addresses (LUCA). The Local Update of Census Addresses program is a decennial census geographic partnership program that allows the Census Bureau to benefit from local knowledge in developing its Master Address File (MAF) for the census. Tribal, state, and local governments contribute to a more complete and accurate census for their community by reviewing and commenting on the list of housing unit and group quarters addresses that the Census Bureau will use to deliver questionnaires within their community.
  • New Residential Construction Program. The 2010 New Residential Construction program ensured that the Census Bureau's address list is as complete and accurate as possible by Census Day, April 1, 2010. The Census Bureau updated its address list by field canvassing all blocks in the spring and summer of 2009.
For more information about these programs and to learn about other georgraphic programs conducted by the Census Bureau, visit the agency's Geographic Programs page.

Georgraphic Products

Center of Population
View larger image

The Center of the United States'
population as of Census 2000.

  • State and County QuickFacts. State and County QuickFacts are frequently requested summary profiles. These profiles are available for the nation, states, counties, and large cities. Student State Facts contains similar profiles as QuickFacts, but are specifically developed for use by a younger audience.
  • Topologically Integrated Geographic Encoding and Referencing (TIGER) system. The Census Bureau's TIGER system supplies spatial extracts from the Census Bureau's MAF/TIGER database. Maps contain features such as roads, railroads, rivers, as well as legal and statistical geographic areas. The files are available to the public free-of-charge, and are typically used to provide the digital map base for a Geographic Information System or for mapping software. Although the maps do not include demographic data, they contain geographic entity codes that can be linked to the Census Bureau's data available on American FactFinder.
  • American FactFinder. The Census Bureau's American FactFinder contains thematic maps showing geographic patterns in statistical data, such as population or median income, displayed as color-coded areas on a map. Popular maps show data for the United States by state, as well as maps displaying data for smaller geographic areas (counties, census tracts, etc.).
  • Voting District/State Legislative District Outline Maps. These county-based maps show outlines of voting districts and/or state legislative districts for states that participated in the 2000 Census Redistricting Data Program.

For more information:

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Source: U.S. Census Bureau | Census History Staff | Last Revised: December 05, 2022