Resident Population in Washington County, OK was 53.70600 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Washington County, OK reached a record high of 53.85900 in January of 1983 and a record low of 41.10000 in January of 1972. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Washington County, OK - last updated from the United States Federal Reserve on May of 2024.