Hartsville is the largest city in Darlington County, South Carolina, United States. The population was 7,764 at the 2010 census. Mel Pennington is the current mayor. Hartsville was chosen as an All-America City in 1996 and again in 2016. Hartsville has also been a National Arbor Day Foundation Tree City since 1986. Hartsville is the home of Coker College and a branch of Florence–Darlington Technical College.