Barnwell is a city in Barnwell County, South Carolina, United States, located along U.S. Route 278. The population was 4,750 at the 2010 census. It is the county seat of Barnwell County.GeographyBarnwell is located east of the center of Barnwell County at . Turkey Creek, a tributary of the Salkehatchie River, runs through the city just west of the downtown, and includes a small impoundment known as Lake Brown in the north part of the city.U.S. Route 278 passes through the city, leading south to Allendale and northwest to Augusta, Georgia. State highways 3, 70, 64 also pass through the city; SC 64 leads west 6mi to the east entrance of the Savannah River Site, which is a nuclear reservation.According to the United States Census Bureau, Barnwell has a total area of 20.7km2, of which 20.3km2 is land and 0.4km2, or 1.86%, is water.DemographicsAs of the census of 2000, there were 5,035 people, 2,035 households, and 1,353 families residing in the city. The population density was 659.5 people per square mile (254.8/km²). There were 2,304 housing units at an average density of 301.8 per square mile (116.6/km²). The racial makeup of the city was 49.81% White, 47.37% Black, 1.05% Asian, 0.40% Native American, 0.04% Pacific Islander, 0.34% from other races, and 0.99% from two or more races. Hispanic or Latino of any race were 0.62% of the population.
