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Microdata Geography Update Planned for 2021

Public Use Microdata Areas, or PUMAs, are nonoverlapping, statistical geographic areas that partition each state into geographic areas containing no fewer than 100,000 people each.

In 2021, the Tennessee State Data Center will lead an update to the PUMA boundaries. Although no criteria have been published, the process likely will be focused on identifying PUMAs with more than 200,000 people that could be split into multiple area. Existing PUMA boundaries falling within the specified population thresholds are often preserved to facilitate comparisons over time.


The Public Microdata Use Sample (PUMS) and the associated PUMA geography, are anonymized single-person and single-household responses to American Community Survey questions. One-year PUMS samples provide responses for about 1 percent of the nation in a format allowing custom analysis that is much more flexible than the aggregate data obtained through data.census.gov.

In the fall of 2020, the U.S. Census Bureau will ask TNSDC to lead a review and update of the state’s PUMAs delineated for the 2010 Census. A 90-day review period is provided for the preparation of the 2020 PUMA submission and will occur in 2021.

Interested data users, including those in state and local governments, as well as regional planning agencies or organizations will be asked to provide input to help ensure that Tennessee’s PUMAs meet the needs of a variety of data users. Collaboration between TNSDC and areas exceeding population of 100,000 will be especially important. The Census Bureau only accepts PUMA delineations from each state’s respective state data center.

The expected timeline for the update is:

  • Fall 2020: Overview of the 2020 PUMA proposed criteria and guidelines of PUMAs presented
  • February 2021: End of comment period on PUMA proposal
  • Spring 2021: Final 2020 PUMA criteria and guidelines on the PUMA website
  • Late Spring-Summer 2021: Delineation of 2020 PUMA’s using decennial census results

The 2020 PUMA updates should be available for use with the 2022 American Community Survey data products released in early Q4 of 2022.