Resident Population in Polk County, FL was 818.33000 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Polk County, FL reached a record high of 818.33000 in January of 2023 and a record low of 228.51500 in January of 1970. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Polk County, FL - last updated from the United States Federal Reserve on May of 2024.