Williston is a town in Barnwell County, South Carolina, United States. The population was 3,139 at the 2010 census.The town lies in the center of the Charleston-Hamburg railroad line, the line of the Best Friend locomotive. The train tracks were removed in the 1990s, but the track site has been designated as historically significant by the South Carolina Department of Archives. This section of the train route is now part of the South Carolina Heritage Corridor.There are three schools in the town: Williston-Elko High School, Williston-Elko Middle School, and Kelly Edwards Elementary School. A private school in Blackville, Jefferson-Davis Academy, also serves a portion of the town's population.