Resident Population in Franklin County, ID was 15.49400 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Franklin County, ID reached a record high of 15.49400 in January of 2023 and a record low of 7.37300 in January of 1970. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Franklin County, ID - last updated from the United States Federal Reserve on May of 2024.