When a new law goes into effect next year, the State of Tennessee will now use the Boyd Center to calculate population estimates for revenue distribution, but in the first year of the program, U.S. Census Bureau-produced figures will be adapted for use.
The State of Tennessee recently took steps to change the way that revenues are shared with counties and municipalities after a bill enacting an annual population estimate program was signed into law on May 21, 2025.
The new legislation changes statutes that fixed county and municipal certified populations to the last federal decennial census for the duration of the decade – unless a special census is conducted. Now, most state-shared revenue distribution formulas that include population data will be based on population estimates that are recalculated and published annually. The yearly adjustment will reflect changes to both the population of each community and the overall state population. That means the proportion of funds that communities will receive each year will also change (Figure 1).
Under the terms of the new law, House Bill 780, the Boyd Center at the University of Tennessee is tasked with preparing population estimates and the Department of Economic and Community Development (TNECD) is charged with their review and certification.
The new law becomes effective on January 1, 2026, and the first estimates will be published in the July 1, 2026, report of Certified Population of Tennessee Incorporated Municipalities and Counties.
Figure 1. Effect of Population Change on Aggregate Population and Population Proportion
In this hypothetical example, Anytown, TN has a population of 1,000 people in 2024, and the aggregate population of all municipalities in the state was 100,000. In 2025, Anytown’s population grew to 1,100 people. This change also increases the 2025 aggregate municipal population by 100 people to 100,100.
| 2024 | 2025 | |
|---|---|---|
| Anytown, TN Population | 1,000 | 1,100 (+100) |
| Aggregate TN Municipal Population | 100,000 | 100,100 |
| Anytown Pop. Proportion | 0.010 (1,000 ÷ 100,000 = 0.010) |
0.011 (1,100 ÷ 100,100 = 0.011) |
Certain Tennessee revenues, like sales tax, are distributed to municipalities “in the proportion as the population of each municipality bears to the aggregate population of all municipalities within the state.” Anytown’s 100-person gain increases its share of the aggregate municipal population from 0.010 to 0.011. Therefore, it would also see a slight increase in the proportion of the total sales tax revenues the state shares with municipalities.
What Are Population Estimates and How Will They Be Used?
The Decennial Census, conducted at the start of each decade on April 1, is a constitutionally mandated count of the nation’s resident population. Those counts are collected through self-response on a census form or follow-up by Census workers who visit non-responding households. Data from the Census are available for a variety of geographic levels, but notably include states, counties and municipalities. For decades, Tennessee has used these decennial counts – and self-administered enumerations called a special census – as the basis for its certified population.
Another full headcount is not conducted until the next decade begins. That is where population estimates come in.
A population estimate is a statistical calculation of the number of residents in a specific area at a particular point in time that is derived from data such as administrative records, surveys, and statistical models that account for population changes since the last census.
In the years following the decennial census, the number of residents in the state and each community can be estimated using data that reports or is symptomatic of population change. Data collected by federal agencies and state/local government, including births, deaths, migration, home construction or other factors are used in these calculations.
For example, in the Vintage 2024 Population Estimates, the U.S. Census Bureau reported Tennessee’s population on July 1, 2024, was 7,227,750 people – a net increase of 79,446 residents since 2023. That change was based on administrative data sources and survey data including:
- Births and deaths reported by state health departments to the National Center for Health Statistics
- Net domestic migration rates based on IRS tax returns and Medicare enrollments
- Net international migration primarily based on responses to the American Community Survey
Similar data is used for county-level estimates produced by the agency. At the subcounty-level, data about new housing units reported by local building officials is the primary determinant of population change. States producing their own population estimates vary both in their approach and the administrative data they leverage. Common indicators include school enrollment, driver’s licenses, voter registrations, utility connections, and vehicle registrations, among others.
U.S. Census Bureau Population Estimates To Be Basis for 2026 Tennessee Population Estimates
The reshuffling of Tennessee’s county and municipal population proportions has traditionally come at the start of the decade or after a special census has been certified. To help communities plan for the new mid-decade basis change, the Boyd Center’s July 1, 2026, certified populations will be based on the Vintage 2025 Population Estimates published by the U.S. Census Bureau.
Those figures, which will reflect population on July 1, 2025, will be released on a flow-basis beginning in December when state-level numbers are published. County-level figures will follow in March of 2026. Lastly, municipal and subcounty estimates are scheduled for a Mid-May, 2026 release (Figure 2).
Figure 2: Schedule for Vintage 2025 Population Estimates Showing Population on July 1, 2025. Release dates are subject to change.
The decision to base Tennessee’s first population estimates on a well-established product is intended to provide communities with additional time to prepare for the transition to the new estimate-based revenue sharing model. The Bureau’s Vintage 2024 products can give reasonable guidance about the trajectory of a community’s population since the 2020 Census and can be used to develop an understanding of the expected magnitude of change next year. Those releases can be found on the Tennessee State Data Center website and are featured in county and municipal population estimate dashboards.
Further, it leverages opportunities that the Boyd Center has taken this decade to provide input on the state’s estimates, as the Tennessee liaison to the Federal-State Cooperative for Population Estimates. This includes annual submissions of group quarter population for on-campus housing, correctional facilities and skilled nursing centers across the state. Additionally, the Center works with counties and municipalities to address incomplete or missing reports of new housing units – an important input to the Census Bureau’s municipal population estimates.
However, it is important to note that the Bureau’s estimates cannot be used directly. To comport with the new legislation, three changes have been preliminarily identified.
- Integrate special census results into the Census Bureau population estimates
Special Censuses conducted by the U.S. Census Bureau are incorporated into population estimate products they release. But special censuses certified under Tennessee statutes are not reflected in their estimates. Because the new statute preserves “…the right or ability of a county or municipality to take a special census at any time during the interim between the regular decennial federal census…”, those results will be reviewed for potential integration into the estimates.
- Adjust aggregate population totals to reflect special censuses
Provisions of at least four Tennessee statutes, including TN Code § 54-4-203(a), 57-5-205, 6-51-114 and 67-6-103(a)(3)(A), require that the aggregate population of counties and municipalities be adjusted following the certification of a special census. The U.S. Census Bureau will be consulted to verify how municipal special censuses that they conducted are reflected in county and state aggregate totals. A similar process for incorporating special censuses certified by TNECD will be developed to ensure subcounty and county estimate totals remain consistent at the state-level following the special census adjustments.
- Small area estimates within Urban Services Districts
In metropolitan counties, the number of residents within the Urban Services District (USD), as described in TN Code § 7-2-108(a)(5), serves as the basis for allocating municipal-shared revenues. However, the USD is not a functioning governmental unit, so population estimates are not made available for that geographic area. To make the Census Bureau estimates compatible with the state’s three metropolitan counties, a population estimate for each county’s USD must be generated. This is done by disaggregating it from the estimate for the surrounding consolidated area. A housing unit-based process for doing so was established following the 2020 Census and will be made routine with the annual updates.
Future Plans
After the population estimates law becomes effective in January 2026, the Boyd Center’s work will be largely focused on operationalizing the state’s population estimates program. This will include development of a new certified population report and collaboration with state-agencies that need to ingest the annual figures.
Work will also begin on the development of a robust county and municipal population estimate model that will replace or be used in concert with the Census Bureau estimates in later years. This will include a review of population estimate models used in other states, an evaluation of available symptomatic population change indicators that are available through Tennessee state agencies and finally selection of appropriate estimates methodology for Tennessee. More information on those efforts will be communicated next year.