Unemployment Rate in King County, WA was 4.90% in December of 2025, according to the United States Federal Reserve. Historically, Unemployment Rate in King County, WA reached a record high of 16.10 in April of 2020 and a record low of 2.20 in April of 2007. Trading Economics provides the current actual value, an historical data chart and related indicators for Unemployment Rate in King County, WA - last updated from the United States Federal Reserve on April of 2026.