Clay County is a county in the U.S. state of Tennessee. As of the 2020 census, the population was 7,581. Its county seat and only incorporated city is Celina. Clay County is named in honor of American statesman Henry Clay, member of the United States Senate from Kentucky and United States Secretary of State in the 19th century.

Jackson County is a county located in the U.S. state of Tennessee. The population was 11,617 at the 2020 census. Its county seat is Gainesboro. Jackson is part of the Cookeville Micropolitan Statistical Area.