County Seat: 155 N First Ave., Suite 300, Hillsboro 97124
Phone: 503-846-8611 (General); 503-846-8888 (Court Administrator)
Population (2020): 620,080
Established: July 5, 1843
Elev. at Hillsboro: 196'
Area: 727 sq. mi.
Average Temp.: January 39.9° July 66.6°
Assessed Value: $71,273,364,154
Real Market Value: $131,743,445,322
(includes the value of non-taxed properties)
Annual Precipitation: 37.71"
Economy: Agriculture, horticulture, forest products, food processing, high tech, sports equipment and apparel
Points of Interest
Tualatin Valley orchards and vineyards, Pacific University, Wilson River and Sunset Highway, Hagg Lake, Old Scotch Church
History and General Information
The original four counties created by the Provisional Government of Oregon were Twality, Clackamas, Yamhill and Champoick. Twality was changed to Washington in honor of President George Washington by the Territorial Legislature on September 3, 1849. The actual organization of Washington County government followed several years later.
Now one of the state’s fastest developing areas, the fertile Tualatin Valley was once filled with beaver and was a favorite hunting ground for Hudson’s Bay Company trappers. The first white settlers arrived around 1840, lured by rich soil. Despite its rapid urbanization, the valley still contains prime agricultural land. Many small towns rich in history dot the area. Pacific University, founded as Tualatin Academy in 1849, is one of the oldest colleges in the West. Washington County operates under a home rule charter approved by voters in 1962. The Northwest’s largest enclosed shopping center, Washington Square, is located south of Beaverton.
Commissioners—Chair Kathryn Harrington 2023; Roy Rogers 2025, Nafisa Fai 2025, Pam Treece 2023; Jerry Willey 2023, Dist. Atty. Kevin Barton 2023; Justice of the Peace Dan Cross 2023; Sheriff Pat Garrett 2025; Auditor John Hutzler 2023; Assess./Clerk Margaret Garza; Surv. Scott Young; Co. Admin. Tanya Ange; CIOs Phillip Bransford & Julie McCloud