Resident Population in Jefferson County, WA was 33.71400 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Jefferson County, WA reached a record high of 33.71400 in January of 2023 and a record low of 10.50000 in January of 1971. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Jefferson County, WA - last updated from the United States Federal Reserve on May of 2024.