Darlington is a city located in Darlington County, South Carolina, United States. In 2010, its population was 6,289. It is the county seat of Darlington County. It is part of the Florence, South Carolina metropolitan area. Darlington is known for its Darlington Oak and Spanish moss. Darlington is home to the famous Darlington Raceway, which hosts the annual NASCAR Southern 500 race on Labor Day weekend as well as a 400-mile spring race.