The growth of adult population statewide was strong last year, but Tennessee’s two largest counties both saw population declines among people under age 65.

Tennessee netted a 55,000-person population increase in 2021, but those gains were entirely from people age  20 years and older. The number of children in the state fell slightly.

An analysis of 2021 Census Bureau Population Estimate data showed that the largest population increases were among individuals over age 65. This group grew by almost 31,000 new residents last year; a level that was on pace with last decade’s annual average increase of about 32,000 people in this group.

Young adults age 20 to 44 netted the state an additional 29,000 new residents.

But two age groups saw decreases last year. The number of people age 45 to 64 fell by almost 4,400 people. There were also fewer children.

The number of people under 20 years of age in Tennessee was down by about 400, in large part due to contractions among the cohort of children age zero to four. This reflects both missed conceptions in the early months of the COVID-19 pandemic that pushed births in 2021 to their lowest totals since 2003, and the continued slide of state and national fertility rates.

Source: Vintage 2021 Population Estimates, U.S. Census Bureau.

For the state’s two largest counties, population loss was not limited to just children. March data showed that a net population loss of 11,500 people in Davidson County and a decline of 6,100 in Shelby County were the result of net domestic migration losses – more people moving out than moving into those counties.

The new age data shows that the decreases in these two counties were spread across all groups under age 65.

In Davidson County, the population age 0 to 19 declined by 2.9 percent, losing over 4,800 youth in the one-year stretch. Similar-sized losses among 20 to 24 years old (-4,572 people) and 45 to 65 years old (-4,357) were also reported in 2021.

Although Shelby County’s population losses among those under age 45 were less pronounced than in Davidson County, the county had 4,750 fewer residents aged 45 to 64.

Population estimates for 2021 showed the state’s two largest counties lost population for age groups that were 64 years and younger. The balance of the state’s 93 counties produced strong increases across all age groups.

Setting Perspective for the 2021 Population Estimates

Last year’s population decreases in Davidson and Shelby counties mirrored a national trend. The central county of some of country’s largest metropolitan areas saw significant population decreases in 2021. 51 of the country’s largest 88 cities lost population; a tremendous jump over recent trends.

To a large degree, this was sparked by domestic migration to surrounding counties or to other counties in the U.S. But in those areas, decreases in the number of young adults between age 20 and 29 were particularly evident.

In some ways, the overall population increases that Tennessee experienced in 2021 were remarkable considering the backdrop of the country’s slowest rate of population increase since its founding. Fertility and international migration continue to wither and deaths spiked due to the COVID-19 pandemic leaving the state largely dependent upon domestic migration for future population gains.

Tennessee saw record levels of domestic migration from other U.S. states in 2021. In December, we’ll find out if that continued into 2022.