There are 3 US Post Offices in Edgefield County serving a total of 19,350 residents equating to 6,450 residents per post office. It's estimated that approximately 30,885 packages are handled across the 3 county post offices annually. Edgefield County is a county located on the western border of the U.S. state of South Carolina. As of the 2010 census, its population was 26,985. Its county seat is Edgefield. Edgefield County has as part of its western border the Savannah River; across the river is Augusta, Georgia. Edgefield is part of the Augusta-Richmond County, GA-SC Metropolitan Statistical Area."