Fayette County is a county located in the U.S. state of Tennessee. As of the 2020 census, the population was 41,990. Its county seat is Somerville. The county was named after the Marquis de la Fayette, French hero of the American Revolution. A part of the Memphis, TN-MS-AR Metropolitan Statistical Area, Fayette County is culturally alike to the Mississippi Delta and was a major area of cotton plantations dependent on slave labor in the nineteenth century.