The combined value of farms and rural land for sale in Barnwell County, South Carolina, recently on Land.com was nearly $27 million. This represents approximately 3,000 acres of farms, rural land, hunting land and other land for sale in Barnwell County. Barnwell County ranks 39th out of 46 counties in South Carolina for the total acreage of land currently advertised for sale. Of all land for sale in Barnwell County, Barnwell had the most land for sale. Manufacturing and related services are the largest economic sectors in Barnwell County. Barnwell County is the 30th largest county (557 square miles) in South Carolina. It's located in the Midlands South Carolina region of South Carolina.