Resident Population in Fairfield County, SC was 20.36900 Thous. of Persons in January of 2024, according to the United States Federal Reserve. Historically, Resident Population in Fairfield County, SC reached a record high of 23.86000 in January of 2010 and a record low of 19.80000 in January of 1972. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Fairfield County, SC - last updated from the United States Federal Reserve on April of 2026.