From congressional districts to census blocks to incorporated places, the Census Bureau tabulates data for a wide variety of geographic entities of all shapes and sizes. Each of these geographic entities is categorized as either legal/administrative or statistical. Understanding legal/administrative and statistical entity designations can give you key insights into the way the Census Bureau maintains and tabulates data for geographic areas.

The names and boundaries of legal/administrative geographic entities are defined in official documentation. Common types of official documentation used to define geographic areas include treaties, charters, legislation, resolutions and ordinances.

Elected government officials and/or stakeholders usually represent legal/administrative geographic areas. The Boundary and Annexation Survey (BAS) happens on a mostly annual basis, where county, incorporated place and minor civil division governments are permitted to submit boundary updates to the Census Bureau. Newly incorporated places that want to be considered legal/administrative geographic entities, and participate in the BAS Program, are required to submit new incorporation papers (legal documentation) and a map showing the new incorporation boundaries. Visit here to learn more about the BAS.

The Tribal Boundary and Annexation Survey (TBAS) happens on an annual basis and permits updates for federally recognized American Indian reservations and/or off reservation trust lands. The School District Review Program (SDRP) happens every two years and permits states to update elementary, secondary and unified school districts.

Legal/administrative entities the Census Bureau collects boundaries and tabulates data for include:

• Alaska Native Regional Corporation (ANRC)
• Congressional District
• Consolidated City
• County or equivalent (Alaska boroughs, Louisiana parishes, Puerto Rico municipios and independent cities)
• Federal American Indian Reservation and Tribal Subdivision (Federal AIR)
• Hawaiian Home Land (HHL)
• Incorporated Place
• Minor Civil Division (MCD)/Barrio and Barrio-Pueblo
• School District (Elementary, Secondary and Unified)
• State American Indian Reservation (state AIR)
• State and State Equivalent

The Census Bureau and other organizations create statistical geographic areas for data tabulation and presentation purposes. Unlike legal/administrative geographic entities, statistical geographic entities do not require official documentation for their creation and are not usually represented by government officials or stakeholders.

Timelines for the creation of statistical geographic entities often differ from those of legal/administrative geographic entities, as most statistical geographies are updated once every ten years in preparation for, or as a result of, decennial census data tabulation. The Office of Management and Budget (OMB) is responsible for delineating metropolitan and micropolitan statistical areas (MSAs) and related statistical areas and updates them at differing time intervals than other statistical entities. The most recent update to MSAs was in February 2013. Click here to learn more about MSAs.

Statistical entities the Census Bureau tabulates data for include:

• Alaska Native Village Statistical Area (ANVSA)
• American Indian Tribal Subdivision (AITS)
• Block
• Block Group
• Census County Division (CCD)
• Census Designated Place (CDP)/Zona Urbana and Comunidad
• Census Tract
• Combined Statistical Area (CSA)
• County Equivalent (Census Areas in Alaska)
• Metropolitan Division
• Metropolitan & Micropolitan Statistical Area (MSA)
• New England City and Town Area (NECTA)
• Oklahoma Tribal Statistical Area (OTSA)
• Public Use Microdata Area (PUMA)
• State Designated Tribal Statistical Area (SDTSA)
• Tribal Block Group
• Tribal Designated Statistical Area (TDSA)
• Tribal Tract
• Urban Area
• ZIP Code Tabulation Area (ZCTA)

Data users rely on data for many legal/administrative and statistical geographic areas alone or in combination with one another. In many cases, legal and statistical geographies in combination provide a greater number of demographic data analysis and interpretation possibilities than either type of geography on its own. For instance, the nesting relationship of census blocks within incorporated places becomes significant when a data user wants to download demographic data for smaller areas within incorporated places. The same can be said for census tracts that nest within counties and many other combinations of legal/administrative and statistical entities.