Scott County is a county located in the U.S. state of Tennessee. As of the 2020 census, its population was 22,039, down from 22,228 at the 2010 census. Its county seat is Huntsville and the largest town is Oneida. Scott County is known for having seceded from Tennessee in protest of the state's decision to join the Confederacy during the Civil War, and subsequently forming The Free and Independent State of Scott.