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. Founded in 1835, Aiken was named after William Aiken, the president of the South Carolina Railroad. It became part of Aiken County when the county was formed in 1871.