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Geography Boundaries by Year

Vintage of Geographic Areas for ACS Estimates

The ACS typically publishes estimates using the latest available geographic boundaries (also known as "vintages"). For ACS 5-year estimates, use the last year of the estimate period to determine the vintage. For example, the following datasets use the same vintages of geographic boundaries:

  • 2021 ACS 1-year estimates
  • 2017-2021 ACS 5-year estimates

To learn more about geographic concepts used in the ACS, check out our geographic handbook Geography and the American Community Survey: What Data Users Need to Know.

2021
  • 2021
  • 2020
  • 2019
  • 2018
  • 2017
  • 2016
  • 2015
  • 2014
  • 2013
  • 2012
  • 2011
  • 2010
  • 2009
2021

Legal Areas

Legally defined geographic areas used in the ACS are updated on an annual basis from a variety of programs, including: the Boundary and Annexation Survey (BAS), the Redistricting Data Program and the School District Review Program

Summary Level
Geographic Area
Vintage of Geographic Area for 2021 ACS Estimate Year

040    

State and State Equivalent

January 1, 2021

050

County or equivalent (Alaska boroughs, Louisiana parishes, Puerto Rico municipios, independent cities)

January 1, 2021


County Subdivision

067

Township, Minor Civil Division (MCD)/Barrio and Barrio-Pueblo

January 1, 2021


Place

160

Incorporated Place

January 1, 2021


American Indian/Alaska Native/Hawaiian Home Land

230

Alaska Native Regional Corporations (ANRCs)

2020 Census

250/252/254

Federal American Indian Reservation (federal AIR)

January 1, 2021

250/252

State American Indian Reservation (state AIR)

2020 Census

251

American Indian Tribal Subdivision, federal AIR

January 1, 2021

250/254

Hawaiian Home Land (HHL)

2020 Census


Other Legal Areas

500

Congressional District, Delegate District DC, Resident Commissioner District PR

116th Congress of the United States/4

610/620

State Legislative Districts (Upper and Lower Chambers)

2018 Legislative Session Year/4

950/960/970

School District (Elementary, Secondary, Unified)

January 1, 2021

170

Consolidated City

January 1, 2021

Statistical Areas

For statistical areas, boundary changes are mostly associated with updates from each decennial census. Statistical areas are designed to have stable boundaries over time.

Summary Level
Geographic Area
Vintage of Geographic Area for 2020 ACS Estimate Year

050

County Equivalent (Census Areas in Alaska)

January 1, 2021


County Subdivision

060

Census County Division (CCD)

2020 Census/1


Place

160

Census Designated Place (CDP)/Zona Urbana and Comunidad

2020 Census/1


American Indian/Alaska Native/Hawaiian Home Land

250/252

Tribal Designated Statistical Area (TDSA)

2020 Census

250/252

State Designated Tribal Statistical Area (SDTSA)

2020 Census

250/252

Oklahoma Tribal Statistical Area (OTSA)

2020 Census

251

American Indian Tribal Subdivision (within OTSA)

2020 Census

256

Tribal Tract

2020 Census/1

258

Tribal Block Group

2020 Census/1

250/252

Alaska Native Village Statistical Area (ANVSA)

2020 Census


Other Statistical Areas

310

Metropolitan Statistical Area/Micropolitan Statistical Area

March 6, 2020/3

312

Metropolitan Statistical Area/Micropolitan Statistical Area - Principal City

March 6, 2020/2,/3

350

New England City and Town Area (NECTA)

March 6, 2020

352

New England City and Town Area - Principal City

March 6, 2020/2

400

Urban Area

2010 Census/4

140

Census Tract

2020 Census/1

150

Census Block Group

2020 Census/1

795

Public Use Microdata Area (PUMA)

2010 Census/4

860

5-digit ZIP Code Tabulation Area (ZCTA)

2020 Census

 

/1Changes to the boundaries of legal areas may cause complementary changes to the boundaries of selected statistical areas.

/2While the American Community Survey (ACS) data generally reflect the Office of Management and Budget (OMB) definitions of metropolitan and micropolitan statistical areas; in certain instances the names, codes, and boundaries of the principal cities shown in ACS tables may differ from the OMB definitions due to differences in the effective dates of the geographic entities.

/3The Census Bureau is planning on publishing the updated boundaries for this geographic summary level with the 2023 ACS release.

/4The Census Bureau is planning on publishing the updated boundaries for this geographic summary level with the 2022 ACS release.

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