Resident Population in Washington County, ID was 11.42500 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Washington County, ID reached a record high of 11.42500 in January of 2023 and a record low of 7.63300 in January of 1970. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Washington County, ID - last updated from the United States Federal Reserve on May of 2024.