Resident Population in Jefferson County, FL was 15.92100 Thous. of Persons in January of 2024, according to the United States Federal Reserve. Historically, Resident Population in Jefferson County, FL reached a record high of 15.92100 in January of 2024 and a record low of 8.50000 in January of 1971. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Jefferson County, FL - last updated from the United States Federal Reserve on April of 2026.