The American Community Survey (ACS) publishes estimates using vintages, the latest available geographic boundaries. Legal areas are updated every year or every other year, and generally reflect the geographic boundaries as of January 1 of the estimate year. For example, 2022 ACS 1-year, as well as 2018-2022 ACS 5-year estimates use the geographic area boundaries effective as of January 1, 2022.
Many statistical areas are updated once per decade to reflect the most recent decennial census. Beginning with the 2020 ACS data products, most statistical areas reflect 2020 Census geographic definitions and boundaries. The 2019 and earlier ACS data products use mostly 2010 Census statistical definitions.
For more information, visit the Geography Boundaries by Year page or the Geography and the ACS: What Data Users Need to Know handbook. View the full list of geographies for which ACS data are published on the Areas Published page.