Yemassee is a small Lowcountry town in Beaufort and Hampton counties in the U.S. state of South Carolina. The population was 1,027 at the 2010 census. Yemassee is near the borders of Colleton and Jasper counties. The town is divided by the county line between Beaufort and Hampton counties, which follows the roadbed of the CSX railroad. Most of the town's population presently lies within Hampton County. As defined by the U.S. Census Bureau, the Beaufort County portion of Yemassee is included within the Hilton Head Island-Bluffton-Beaufort, SC Metropolitan Statistical Area. Yemassee hosts one of the few commercial breeding facilities of non-human primates in the entire United States, Alpha Genesis, Inc., which serves as a major employer for the town. Also, the Frank Lloyd Wright-designed Auldbrass Plantation house and outbuildings lie just outside the town limits of Yemassee.