The Boundary and Annexation Survey (BAS) fulfills the agency’s responsibility as part of the National Spatial Data Infrastructure, for which the Office of Management and Budget (OMB) Circular A–16 designates the Census Bureau as the lead federal agency for maintaining national data about legal government boundaries, as well as statistical and administrative boundaries. BAS supports the geospatial data steward responsibilities of the Geospatial Data Act, the Evidence Act, OMB E-Gov, the Federal Geographic Data Committee, Data.gov, GeoPlatform.gov, the National Map, the Geographic Names Information System, and the Geospatial One-Stop.

View the OMB Federal Register Notice for BAS

Outreach

The Census Bureau collects legal boundary, census designated place, and contact updates from tribal, state, and general-purpose local governments in all 50 states,  the District of Columbia, and Puerto Rico. Governments are first contacted during annual response where they are asked if they have legal boundary, census designated place, or contact updates to report. Those indicating they have updates to provide can choose to create a submission using an approved response method. Those governments that do not respond to annual response or those governments that indicate they have updates to provide are followed up with during BAS non-response follow-up.

BAS Submissions

Tribal, state, and general-purpose local governments with boundary updates can choose to create a submission using either digital or paper response methods during annual response. The data provided to the partners, by the Census Bureau, are derived from its Master Address File and Topologically Integrated Geographic Encoding and Reference (MAF/TIGER) System. The boundary data reflects updates reported by partners through the prior year's BAS.

BAS Results

The Census Bureau provides the results of BAS to the public as part of the agency’s annual release of TIGER/Line products and via the TIGERweb online mapping application. The public and data users rely on the annual BAS boundaries as the official federal representation of boundaries for legal governments.

Numerous federal programs rely on accurate boundaries from each BAS, including:

• The U.S. Geological Survey depicts the annual BAS boundaries on the National Map online.
• The Department of Housing and Urban Development uses BAS boundaries to determine jurisdictional eligibility for various grant programs, such as the Community Development Block Grant program.
• The Department of Agriculture uses BAS boundaries to determine eligibility for various rural housing and economic development programs.

The Census Bureau uses BAS results to support several programs, including:

• Congressional and State Legislative redistricting,
• The decennial census and related preparatory tests,
• The Economic Census, and
• The Special Census Program.

In addition, the American Community Survey uses BAS boundaries to tabulate survey results, and the Population Estimates Program uses BAS to ensure that the most current boundaries are available in the annual release of population estimates.

Legal Disputes

The Census Bureau will not make any boundary change that affects adjacent legal governments without the appropriate documentation. Please review any changes that affect adjacent governments to determine if they are intentional legal changes.

If the Census Bureau discovers that an area of land is in dispute between two or more jurisdictions, the Census Bureau will not make any boundary corrections until the parties come to a written agreement, or there is a documented final court decision regarding the dispute.

To learn more, please contact the Census Bureau Legal Office at 1-301-763-2918.

For disputes involving tribal areas, the Census Bureau must defer to the Office of the Solicitor at the Department of the Interior for a legal opinion. Often complicated land issues require an extended period for resolution, and in those cases, the Census Bureau will retain the current boundary in the database until a legal opinion is issued by the Solicitor's office.