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The 2021 Boundary and Annexation Survey (BAS) maps display the updated legal boundary and names valid through January 1, 2020 for all governments that participated in the 2020 BAS. The file name for the 2021 BAS maps have the prefix “BAS21”.

Map file naming conventions for each government type are detailed below.

American Indian Areas (AIAs)

AIAs include federally recognized American Indian Reservations, American Indian off-reservation trust land, and American Indian tribal subdivision boundaries. AIA maps can be found by opening the American Indian Areas link on the maps page.

The file naming convention for AIAs is as follows:  BAS21R4<st><tribal code><tribal area code>.pdf,
where <st> represents the two digit state Federal Information Processing Standards (FIPS) code, <tribal code> represents the four digit tribal code, and <tribal area code> represents the four digit tribal area code. An example of an AIA file name is:  BAS21R49900090495.pdf. Please note that the <st> designation is “99” and does not refer to the state where the AIA is located.

Hawaiian Home Lands (HHLs)

An area created and held in trust for the benefit of native Hawaiians by the state of Hawaii, pursuant to the Hawaiian Homes Commission Act of 1920, as amended. HHL maps can be found by opening the link to the list of HHLs on the maps page.

The file naming convention for HHLs is as follows: BAS21R4<st><yyyy><zzzz>.pdf,
where <st> represents the two digit state FIPS code, <yyyy> represents the four digit HHL state office code, and <zzzz> represents the four digit HHL code. An example of a HHL file name is: BAS21R49903035026.pdf. Please note that the <st> designation is “99” and does not refer to the state where the HHL is located.

Consolidated Cities

A type of incorporated place that contains one or more other incorporated places that continue to function as separate government within a consolidated government. Consolidated City maps can be found by opening the link to the state of your interest and then opening the link to the list of consolidated cities for that state.

The file naming convention for Consolidated Cities is as follows: BAS21CC0<st>000<yyyyy>.pdf,
where <st> represents the two digit state code, and <yyyyy> represents the five digit Consolidated city FIPS code. An example of a Consolidated City file name is: BAS21CC00900047500.pdf.

Counties

The primary legal division of states except in the states of Alaska and Louisiana. In Alaska, Census Areas and Boroughs are recognized by the Census Bureau as a county equivalent. In Louisiana, Parishes are recognized by the Census Bureau as a county equivalent. In Puerto Rico, the Census Bureau recognizes Municipios as the county equivalent. County maps can be found by opening the link to the state of your interest, and then opening the link to the list of counties in that state.

The file naming convention for Counties is as follows: BAS21C2<st><cou>00000.pdf,
where <st> represents the two digit state FIPS code, and <cou> represents the three digit county FIPS code. An example of a County file name is: BAS21C2020200000.pdf.

Incorporated Places

Incorporated places are incorporated under state law as a city, city and borough, municipality, borough, or village that has legally prescribed limits, powers, and functions. Incorporated place maps can be found by opening the link to the state of your interest, and then opening the link to the list of counties in that state.

The file naming convention for Incorporated Places is as follows: BAS21P1<st>000<place>.pdf,
where <st> represents the two digit state FIPS code, and <place> represents the five digit place FIPS code. An example of an Incorporated Place file name is: BAS21P10600000947.pdf.

Minor Civil Divisions (MCDs)

MCDs are the primary government or administrative divisions of counties and county equivalents in 29 states. MCDs represent many different kinds of legal governments with a wide variety of government and/or administrative functions. MCDs are variously designated as American Indian reservations, assessment districts, boroughs, charter townships, election districts, election precincts, gores, grants, locations, magisterial districts, parish governing authority districts, plantations, precincts, purchases, road districts, supervisors’ districts, towns, and townships. MCD maps can be found by opening the link to the state of your interest, and then opening the link to the list of MCDs in that state.

The file naming convention for MCDs is as follows: BAS21M3<st><cou><MCDcd>.pdf,
where <st> represents the two digit state FIPS code, <cou> represents the three digit county FIPS code, and <MCDcd> represents the five digit MCD FIPS code. An example of a MCD file name is: BAS21M31700123412.pdf.

Mapsheet Types

The intent of this map is to show the subject government on the fewest number of map sheets possible at the maximum practical scale based on the size and shape of the government and feature density. The government can be covered by one or more parent map sheets at a single scale. Inset map sheets at larger scales are created as required to show the map content described above. An index map showing the full extent of the government and the map sheet configuration is included for governments requiring more than one parent map sheet. All map sheets are included in a single PDF file.

Related Information


REFERENCE MAP

2021 BAS Maps
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