Tennessee’s proposed 2020 Public Use Microdata Area boundaries (PUMAs) were finalized and submitted to the U.S. Census Bureau in late January 2022 – the last in a series of steps before the updated boundaries are incorporated into Census Bureau data products beginning later this year.

PUMAs are statistical areas based on counties and census tracts and contain at least 100,000 people. They must also comply with a series of other criteria set by the Census Bureau. A sample of anonymized 2020 Census and American Community Survey responses, called Public Use Microdata Samples (PUMS) are published for each PUMA and for each state. The individual responses enable analysts and researchers to create custom data tabulations beyond those published in precompiled tables on data.census.gov.

State Data Centers across the country are designated with the responsibility of delineating new PUMA boundaries following the release of the 2020 Census Redistricting Data. In December 2021, the Tennessee State Data Center floated the state’s draft alternatives. At a January 11th webinar, the two proposals were reviewed and feedback was collected. The alternatives presented competing ideas about how to arrange the PUMAs following a decade of population changes across the state.

• Alternative 1 – Minimal changes to existing PUMAs to preserve continuity between decades
• Alternative 2 – Increase data availability and better comply with Census Bureau guidance about PUMA boundaries

The feedback gathered from data users was overwhelmingly in favor of Alternative 2 which sought to both increase the number of PUMAs and to better align the state’s PUMAs with Metropolitan Statistical Areas, among other criteria.

The new PUMAs should be published later this year as part of the Bureau’s 2022 TIGER releases. Feedback from data users also suggested that additional training on the use of PUMS products and Census Bureau tools to access microdata would be beneficial.

Final 2020 Tennessee PUMAs

Filled areas show the final 2020 PUMAs areas. Gray outlines show 2010 boundaries. Use the +/- button in the top left hand corner of the map to zoom in and show more detail.

Summary of 2020 PUMA Changes since 2010

1. Reconfigure Shelby County PUMA’s to meet and maintain required 100,000-person minimum
   Several PUMAs within the southern part of Shelby County were adjusted to achieve the necessary 100,000-person minimum. Additional area was also added to two PUMA’s on the southern edge of Shelby County to ensure these geographies maintain sufficient population throughout the upcoming decade since both had lost population in the last ten years.
2. Split existing PUMA’s with 2020 population in excess of 200,000 people
   • Montgomery & Stewart Counties–Clarksville City PUMA was divided into two standalone PUMAs in Clarksville and Montgomery County. Stewart County was added into an adjacent area.
   • Williamson County–Franklin & Brentwood Cities PUMA–In 2020, this PUMA’s population had grown to 233,726 people. An area entirely within the City of Clarksville corporate limits, that exceeded 100,000 people, was added to create a new PUMA.
3. Maximize interior delineations for all counties with greater than 300,000 people
   There are several counties where additional interior delineations would result in new PUMA’s being created. These include:
   • Nashville/Davidson County (pop. 715,884) – The county was reconfigured with six PUMAs and boundaries that roughly align with Metro Nashville Planning Subareas – stable areas used for community planning work.
   • Knox County (pop. 478,971) – increase from three to four PUMA’s by building areas which coincide with the county’s planning sectors – stable areas built on census tracts
   • Rutherford County (pop. 341,486) – increase from two to three PUMA’s that includes one PUMA for the Murfreesboro area and another roughly encompassing the municipalities of Smyrna and La Vergne.
4. Create standalone PUMAs for counties with more than 100,000 people
   One additional PUMA was created for Maury County. Bradley County, which exceeds the 100,000-person PUMA minimum, remains in a PUMA connected to Polk County to encompass the entirety of the Cleveland, TN Micropolitan area
   • Maury County (pop. 100,974)
5. Improve alignment with 2018 core-based statistical areas boundaries
   Several changes were made to better align metropolitan and micropolitan areas with PUMA boundaries. Where possible, PUMA’s were created to contain:
   • Counties from one metropolitan statistical area
   • Counties from one or more micropolitan statistical areas
   • Areas entirely outside of a core-based statistical areas