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Home > Local > Counties > Washington County

Washington County

A canola field on Mountaindale Road.

A canola field on Mountaindale Road. (Oregon State Archives Photo)

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County Seat: 155 N 1st Ave., Suite 300, Hillsboro 97124
Phone: 503-846-8611 (General); 503-846-8888 (Court Administrator)
Fax: 503-846-4545


Population (2016): 583,595
Established: July 5, 1843
Elev. at Hillsboro: 196'
Area: 727 sq. mi.
Average Temp.: January 39.9° July 66.6°
Assessed Value: $59,446,698,455
Real Market Value: $108,038,519,766
Annual Precipitation: 37.71"
Economy: Agriculture, horticulture, forest products, food processing, high tech, sports equipment and apparel


Washington County map

Related resources
Historical Records Inventory
Scenic Image
"County QuickFacts" (population and economic data from U.S. Census Bureau)
County Seat Map (from Yahoo! Maps)
County Map (from ODOT)


Incorporated cities
Banks | Beaverton | Cornelius | Durham | Forest Grove | Gaston | Hillsboro | King City | North Plains | Portland | Rivergrove | Sherwood | Tigard | Tualatin | Wilsonville


Points of interest
ualatin Valley orchards and vineyards, Pacific University, Wilson River and Sunset Highways, 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.


County officials
Commissioners—Chair Andy Duyck 2019, Greg Malinowski 2019, Roy Rogers 2021, Dick Schouten 2021, Bob Terry 2019; Dist. Atty. Robert Hermann 2019; Justice of the Peace Dan Cross 2023; Sheriff Pat Garrett 2021; Auditor John Hutzler 2019; Assess./Clerk Richard Hobernicht; Surv. James Elam; Co. Admin. Robert Davis; Chief Info. Officer Phillip Bransford


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