Washington County, Oregon

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Washington County, Oregon
Washington County Courthouse (Washington County, Oregon scenic images) (washD0007).jpg
Washington County Courthouse
Map of Oregon highlighting Washington County
Location in the state of Oregon
Map of the United States highlighting Oregon
Oregon's location in the U.S.
FoundedJuly 5, 1843
Largest cityHillsboro
 • Total726 sq mi (1,880 km2)
 • Land724 sq mi (1,875 km2)
 • Water3 sq mi (8 km2), 0.36%
 • (2010)529,710
 • Density732/sq mi (282.5/km²)
Congressional district1st
Time zonePacific: UTC-8/-7
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For counties with a similar name, see Washington County (disambiguation).
Washington County, Oregon
Washington County Courthouse (Washington County, Oregon scenic images) (washD0007).jpg
Washington County Courthouse
Map of Oregon highlighting Washington County
Location in the state of Oregon
Map of the United States highlighting Oregon
Oregon's location in the U.S.
FoundedJuly 5, 1843
Largest cityHillsboro
 • Total726 sq mi (1,880 km2)
 • Land724 sq mi (1,875 km2)
 • Water3 sq mi (8 km2), 0.36%
 • (2010)529,710
 • Density732/sq mi (282.5/km²)
Congressional district1st
Time zonePacific: UTC-8/-7

Washington County is one of 36 counties in the U.S. state of Oregon. As of the 2010 census, the population was 529,710,[1] making it the second most populous county in the state.[2] The seat and largest city is Hillsboro.[2][3] Other cities include Beaverton, Tigard, and Forest Grove, the oldest city in the county.[4]

Originally named Twality when created in 1843, the territorial legislature renamed it for the first president of the United States, George Washington, in 1849. The original boundaries included the entire northwest corner of Oregon before sections became new counties. The Tualatin River and its drainage basin are almost entirely within the county, with the county nearly coterminous with the Tualatin Valley. It is bordered on the west and north by the Northern Oregon Coast Range, on the south by the Chehalem Mountains, and on the north and east by the Tualatin Mountains (or West Hills).

Major roads in the county include small sections of Interstate 5 and Interstate 205, the Sunset Highway, Oregon Route 217, Oregon Route 47, Oregon Route 10, Oregon Route 6, and Oregon Route 8. Public transportation is primarily operated by TriMet and includes buses, the Westside Express Service commuter rail, and MAX Light Rail. Other transportation includes air travel at the Hillsboro Airport, several private airfields and heliports, and heavy rail cargo on several rail lines.

Washington County is included in the Portland metropolitan area.


Current county jail in Hillsboro.

The Provisional Legislature of Oregon created the county as Twality District on July 5, 1843.[5] Twality was one of the original four districts of the Provisional Government of Oregon in Oregon Country along with Clackamas, Champooick (later Marion), and Yamhill counties. Columbia, later known as Hillsboro, was selected as the county seat in 1850. Washington County obtained its present boundaries in 1854 with the creation of Columbia County to the north and Multnomah County to the east.[5]

The construction of Canyon Road to Beaverton helped Portland to consolidate its position as the primary port of Oregon, and defeat the rival efforts of settlements such as Oregon City and Milwaukie.

In November 2004, the County and the City of Beaverton agreed to a plan where the city would annex both unincorporated residential neighborhoods as well as high-value areas of land. This would result with Cedar Hills, Garden Home, Raleigh Hills, West Slope being incorporated by 2010, and the communities of Aloha, Bethany, and Cedar Mill at some point after that.

Those plans have since been put on hold after Beaverton attempted to forcibly annex Nike, Inc.'s World Headquarters, which would have increased Nike's taxes substantially. Nike successfully lobbied the legislature for a law that would prohibit their annexation for 99 years. Since that decision, annexation plans have been halted, and Washington County started urban planning to provide city-level services to the unincorporated urban areas in the county.[6]

On January 1, 2014, 160 acres (65 ha) of Multnomah County in the Bethany area transferred to Washington County.[7] The area had originally been split off from Washington County when Multnomah County was created, and was transferred back to allow for development of the property.[7]


The county is governed by an elected board of five commissioners. The county is divided into four commissioner districts. One commissioner sits for each district, and the fifth commissioner is "at large" and is the Chair of the board.[8]


Washington County generally leans Democratic but can be closely divided. In 2008, Barack Obama won with 59.8% of the popular vote (141,544 total votes) to Republican John McCain's with 37.7% (89,185). For the Senatorial race that year, it was much closer with Democrat Jeff Merkley winning 48.8% of the vote (111,367); Republican Gordon H. Smith won 46.5% of the vote (106,114).[9]


Washington County is centered on a fertile plain that attracted farmers before the first wagon trains. In 1997, orchards covered 8,403 acres (34 km²) of the county's lands and 1,163 acres (4.7 km²) were devoted to vineyards.[citation needed] Agriculture is still a major industry in Washington County, as are lumber, manufacturing, and food processing. (The county is home to Roloff Farms, featured in the TV show Little People, Big World.)

The development of a large electronics industry during the 1980s and 1990s is the dominating factor of the county economy. California-based Intel, Oregon's largest private for-profit employer, has its largest concentration of employees in the county, mainly in Hillsboro.[citation needed] Other technology companies include Electro Scientific Industries, Lattice Semiconductor, FEI Company, Merix, TriQuint Semiconductor, Tektronix, SolarWorld, Planar Systems, and EPSON.[citation needed]

Nike, one of two Fortune 500 corporations based in Oregon, has its headquarters in Washington County. Until it was acquired by IBM, Sequent Computer Systems was headquartered right next door to Nike. The facility is now host to a number of software groups for IBM, including one of its Linux Technology Centers. Other companies with headquarters in Washington County include optical instruments manufacturer Leupold & Stevens, Columbia Sportswear, and Reser's Fine Foods.


Located approximately 20 miles (32 km) to the west of Portland, the county has a total area of 726 square miles (1,881 km²), of which 724 square miles (1,874 km²) is land and 3 square miles (7 km²) (0.36%) is water.[10] The Portland Metro Urban Growth Boundary (UGB) bisects the county. The county's highest point is South Saddle Mountain at 3,464 feet (1,056 m) above sea level in the Northern Oregon Coast Range.[11]

Most of the county is in the Tualatin Valley, which is surrounded by the Tualatin Mountains to the east and north, the Chehalem Mountains to the south, and the Northern Oregon Coast Range to the west and north. In the valley is the only river in the county, the Tualatin River, the Tualatin Plains, and several small hills.[citation needed] The northern and western portions of the county are forested, while the remainder of the county includes urban areas, agricultural lands, and floodplains.[citation needed]

Adjacent counties[edit]

Map of Washington County

Major highways[edit]

National protected areas[edit]


The Tualatin River is the main river in Washington County. Henry Hagg Lake, southwest of Forest Grove, is the largest lake. The Willamette River lies to the east, the Columbia River to the northeast, and the Pacific Ocean to the west of the county.


Historical population
Est. 2012547,6723.4%
U.S. Decennial Census[12]
2012 Estimate[1]
From 2000 to 2007, Washington County's population growth was 14.8%, twice the national average. It was the fastest growing county in the Portland metropolitan area.

As of the census[13] of 2000, there were 445,342 people, 169,162 households, and 114,015 families residing in the county. The population density was 615 people per square mile (238/km²). There were 178,913 housing units at an average density of 247 per square mile (95/km²). The racial makeup of the county was 82.19% White, 1.15% Black or African American, 0.65% Native American, 6.68% Asian, 0.30% Pacific Islander, 5.86% from other races, and 3.17% from two or more races. 11.17% of the population were Hispanic or Latino of any race. 17.2% were of German, 9.9% English, 8.2% Irish and 6.7% American ancestry. 81.7% spoke only English at home, while 9.6% spoke Spanish and 1.2% Vietnamese.

There were 169,162 households out of which 35.60% had children under the age of 18 living with them, 54.50% were married couples living together, 9.00% had a female householder with no husband present, and 32.60% were non-families. 24.70% of all households were made up of individuals and 6.70% had someone living alone who was 65 years of age or older. The average household size was 2.61 and the average family size was 3.14.

In the county, the population was spread out with 26.90% under the age of 18, 9.30% from 18 to 24, 34.10% from 25 to 44, 20.90% from 45 to 64, and 8.80% who were 65 years of age or older. The median age was 33 years. For every 100 females there were 99.10 males. For every 100 females age 18 and over, there were 97.00 males.

The median income for a household in the county was $52,122, and the median income for a family was $61,499. Males had a median income of $43,304 versus $31,074 for females. The per capita income for the county was $24,969. About 4.90% of families and 7.40% of the population were below the poverty line, including 8.30% of those under age 18 and 5.30% of those age 65 or over.


Incorporated cities[edit]

Downtown Beaverton
Downtown Forest Grove in 1920
City1990 population2000 population2010 population[14]IncorporatedNotes
Forest Grove13,55917,70821,0831872
Hillsboro37,52070,18791,6111876County seat
King City2,0601,9493,1111966
Lake Oswego30,57635,27836,6191910Small portion, most in Clackamas County[15]
North Plains9721,6051,9471963
Portland437,319529,121583,7761851Small portion, most in Multnomah County[16]
Rivergrove2943242891971Small portion, most in Clackamas County
Tualatin15,01322,79126,0541913Small portion also in Clackamas County
Wilsonville7,10613,99119,5091969Small portion, most in Clackamas County[17]

Unincorporated communities and CDPs[edit]

See also[edit]


  1. ^ a b "State & County QuickFacts". United States Census Bureau. Retrieved November 15, 2013. 
  2. ^ a b Proehl, Risa S. (March 2009). "2008 Oregon Population Report". Population Research Center. Portland State University. p. 7. Retrieved 2009-05-05. 
  3. ^ "Find a County". National Association of Counties. Retrieved 2011-06-07. 
  4. ^ "Incorporation dates". The Hillsboro Argus. October 19, 1976. pp. Communities, p. 21. 
  5. ^ a b Oregon State Archives: Washington County History
  6. ^ "Appellate court rejects Beaverton annexation". The Oregonian. June 16, 2006. 
  7. ^ a b "County welcomes Area 93 in new year". Hillsboro Tribune. January 10, 2014. Retrieved 11 January 2014. 
  8. ^ Official County web site
  9. ^ David Leip. "Dave Leip's Atlas of U.S. Presidential Elections". Uselectionatlas.org. Retrieved 2013-07-08. 
  10. ^ "US Gazetteer files: 2010, 2000, and 1990". United States Census Bureau. 2011-02-12. Retrieved 2011-04-23. 
  11. ^ Peakbagger.com: South Saddle Mountain, Oregon
  12. ^ "U.S. Decennial Census". Census.gov. Retrieved November 15, 2013. 
  13. ^ "American FactFinder". United States Census Bureau. Retrieved 2008-01-31. 
  14. ^ "2010 Census Redistricting Data (Public Law 94-171) Summary File". American FactFinder. United States Census Bureau. Retrieved August 12, 2011. 
  15. ^ City of Lake Oswego
  16. ^ PortlandOnline
  17. ^ City of Wilsonville

External links[edit]

Coordinates: 45°34′N 123°05′W / 45.56°N 123.09°W / 45.56; -123.09