Chesterfield County is a county located in the U.S. state of South Carolina. As of the 2020 census, its population was 43,273. Its county seat is Chesterfield. The largest community in the county is Cheraw. It is located north of the Midlands, in the Pee Dee region, on its border with North Carolina.

Chesterfield is a town in Chesterfield County, South Carolina, United States. The population was 1,472 at the 2010 census. It is the county seat of Chesterfield County. At the time of the 2010 census, Chesterfield was the least populous of all of South Carolina's county seats.