Aiken is the most populous city in, and the county seat of, Aiken County, South Carolina, United States. According to 2020 census, the population was 32,025, making it the 15th-most populous city in South Carolina, and one of the two largest cities of the Central Savannah River Area.

Aiken County is a county in the U.S. state of South Carolina. As of the 2020 census, its population was 168,808. Its county seat and largest community is Aiken. Aiken County is a part of the Augusta-Richmond County, GA-SC Metropolitan Statistical Area. It is mostly in the Sandhills region, with the northern parts reaching in the Piedmont and southern parts reaching into the Coastal Plain.