Fayette County is a county in the U.S. state of Tennessee. Its county seat is Somerville. Fayette County, Tennessee has a 19 seat legislative body (Board of Commissioners). Fayette County was established in 1824 by the Tennessee General Assembly. Since 2000, Fayette County has been transitioning from a rural area to accommodate the suburban sprawl from Memphis. Although Somerville is the county seat, Oakland is the largest town in the county by population. Fayette County consists of a total of 706 square miles. It is the third largest county in Tennessee by area.