Resident Population in Nassau County, FL was 104.37600 Thous. of Persons in January of 2024, according to the United States Federal Reserve. Historically, Resident Population in Nassau County, FL reached a record high of 104.37600 in January of 2024 and a record low of 20.62600 in January of 1970. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Nassau County, FL - last updated from the United States Federal Reserve on April of 2026.