Darlington County is a county in the U.S. state of South Carolina. As of the 2020 census, its population was 62,905. Its county seat is Darlington. Hartsville is the largest community in the county. Darlington County is home to the Darlington Raceway, which hosts the annual NASCAR Southern 500. Darlington County is also home to Coker College in Hartsville. Darlington County was named by an act in March 1785.

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 Statistical Area.