Oconee is one of the 46 counties in the state of South Carolina. It was created in 1868 from part of Pickens County. As of the 2010 census the population was 74,273, up from 66,215 in 2000. The county seat is Walhalla, and the largest city is Seneca. The county has 674 square miles (1,746 km2) of area, of which 625 sq mi (1,619 km2) is land.
It is bordered by Pickens County to the east, Anderson County to the southeast, Hart County, Georgia and Franklin County, Georgia to the south, Stephens County, Georgia to the southwest, Habersham County, Georgia and Rabun County, Georgia to the west, Macon County, North Carolina to the northwest, Jackson County, North Carolina to the north and Transylvania County, North Carolina to the northeast. Oconee is one of the few counties to border 10 other counties.