Tennessee "By the numbers" according to census estimates as published on the website World Population Review.

In 2019, the most populous county in Tennessee is Shelby County, home of Memphis, with 936,961 residents. This represents very slight growth of 0.91% since the 2010 census. Shelby County is followed by Davidson County (691,243), Knox County (461,860), Hamilton County (361,613), and Rutherford County (317,157) as the only Tennessee counties with a population of more than 300,000. Of these counties, Rutherford County has seen the highest population growth of 20.25%.

Tennessee Counties with Fewest Residents

Pickett County is the least populated county in Tennessee with a population of just 5,073. This represents flat population growth since the census. Tennesse has several other counties with a population below 10,000 including Van Buren County (5,742), Moore County (6,384), Hancock County (6,600), Lake County (7,468), Clay County (7,703), Perry County (7,975), and Houston County (8,213). Most of these counties have experienced negative growth since the census. Of these, Lake County has experienced the most significant population loss of -4.60%.

Tennessee Counties with Rapid Growth

Trousdale County has experienced the highest growth rate in the state since the census at 28.05%, bringing its population to 10,083.

Their secret? They added a prison whose population gave them a big boost! Also, 10% of Trousdales population is behind bars. 

The only other counties with population growth over 15% are Rutherford County (20.25%), Wilson County (18.98%), and Montgomery County (15.60%). Lauderdale County has experienced the greatest population loss with a growth rate of -8.82%, bringing its population down to 25,274.