The Boundary Annexation Survey (BAS) Submission Checklist for Local Governments

The Boundary Annexation Survey (BAS) Submission Checklist for Local Governments

By EditorJul 14, 20260 Comments
The Boundary and Annexation Survey (BAS) is the Census Bureau's annual check-in with local government on where its legal boundaries actually are. Each year the Bureau contacts federally recognized American Indian areas, counties and county equivalents, incorporated places, and minor civil divisions, asking each to confirm that the Bureau has the correct boundary, name, and status for that government. The public and data users rely on the annual BAS boundaries as the official federal representation of boundaries for legal governments. The Census Bureau maintains this data in its MAF/TIGER System and publishes the results through the annual TIGER/Line release. For…
DATA and TECHNOLOGY, Local Redistricting, , ,
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BBSP vs. BAS: Two Census Programs, Two Crucial Jobs

BBSP vs. BAS: Two Census Programs, Two Crucial Jobs

By EditorJun 04, 2026
The Boundary and Annexation Survey (BAS) and the Block Boundary Suggestion Project (BBSP) are often conflated; both involve local geography and the Census Bureau, but they do different jobs. BAS is the Bureau's annual survey to keep the legal boundaries and names of governments current, such as city limits, county lines, township boundaries, and tribal areas. BBSP is a once-a-decade phase of the Redistricting Data Program in which a state suggests which features the Bureau should use as statistical census tabulation block (census block) boundaries. The other differences follow from that split. BAS runs every year, and each eligible government…
DATA and TECHNOLOGY, Local Redistricting, , , ,
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Why the Boundary and Annexation Survey (BAS) Matters for Local Redistricting Officials

Why the Boundary and Annexation Survey (BAS) Matters for Local Redistricting Officials

By EditorDec 15, 2025
Every year, the U.S. Census Bureau invites tribal, state, and general-purpose local governments, counties, cities, towns, and minor civil divisions to verify that its legal-boundary file is still accurate. This verification program is the Boundary and Annexation Survey (BAS). For local officials, keeping your boundaries current is not just cartographic housekeeping. BAS data feeds the American Community Survey, the Population Estimates Program, and the TIGER/Line layers that nearly all redistricting platforms rely on. Accurate boundary lines also protect your jurisdiction’s share of the roughly $2.8 trillion in annual federal funds that are allocated by geography. Who should participate and what’s…
Census Data and Geography, Local Redistricting, , ,
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