Sumter is a city in and the county seat of Sumter County, South Carolina, United States. The city makes up the Sumter, SC Metropolitan Statistical Area. Sumter County, along with Clarendon and Lee counties, form the core of Sumter–Lee–Clarendon tri-county area of South Carolina that includes three counties straddling the border of the Sandhills, Pee Dee, and Lowcountry regions. The population was 43,463 at the 2020 census, making it the 9th-most populous city in the state.

Sumter County is a county located in the U.S. state of South Carolina. As of the 2020 census, the population was 105,556. Its county seat is Sumter.