Hartsville is the largest city in Darlington County, South Carolina, United States. It was chartered on December 11, 1891. As of the 2020 census, Hartsville had a population of 7,446. By Zip code the population of Greater Hartsville is approximately 30,000. 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.