Lone Oak is an unincorporated community and census-designated place in southern Sequatchie County, Tennessee, United States. It lies along U.S. Route 127 south of the city of Dunlap, the county seat of Sequatchie County. Its elevation is 2,001 feet. As of the 2020 census, its population was 1,198, down from 1,206 at the 2010 census. Lone Oak is part of the Chattanooga, TN–GA Metropolitan Statistical Area.