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Washington County, Oregon

Washington County is a county located in the U.S. State of Oregon. Originally called Twality, the Territorial Legislature renamed this county for the first president of the United States, George Washington on September 3, 1849.Washington County is home to 445,342 (2000 Census) residents. The county seat is Hillsboro.

Table of contents
1 Economy
2 Geography
3 Demographics
4 History
5 Cities and towns


Washington County is centered on a fertile plain that attracted farmers before the first wagon trains. In 1997, orchards covered 8,403 acres of the county's lands and 1,163 acres were devoted to vineyards.

The development of a large electronics industry during the last two decades is the dominating factor of the economy of this county. Intel, Oregon's largest private employer, has here its largest concentration of employees outside of its California home. Agriculture is still a major industry in Washington County, as are lumber, manufacturing, and food processing.

Washington County is the location for the corporate headquarters of Nike, the only corporation based in Oregon large enough to be included in the Fortune 500 list. 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.


Located to the west of Portland, this county has a total area of 1,881 km² (726 mi²). 1,874 km² (724 mi²) of it is land and 7 km² (3 mi²) of it is water. The total area is 0.36% water.

Major highways


As of the census2 of 2000, there are 445,342 people, 169,162 households, and 114,015 families residing in the county. The population density is 238/km² (615/mi²). There are 178,913 housing units at an average density of 95/km² (247/mi²). The racial makeup of the county is 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 are Hispanic or Latino of any race.

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

In the county, the population is 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 are 65 years of age or older. The median age is 33 years. For every 100 females there are 99.10 males. For every 100 females age 18 and over, there are 97.00 males.

The median income for a household in the county is $52,122, and the median income for a family is $61,499. Males have a median income of $43,304 versus $31,074 for females. The per capita income for the county is $24,969. 7.40% of the population and 4.90% of families are below the poverty line. Out of the total people living in poverty, 8.30% are under the age of 18 and 5.30% are 65 or older.


The Provisional Legislature created Washington County as Twality District on July 5, 1843, as one of the original four districts of the Oregon territory 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.

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 as Oregon City and Milwaukie.

Washington county has been a stronghold of the Republican Party, who have consistently registered a majority of voters as members ever since its creation, despite Washington County's evolution from a farming economy to a suburb of Portland.

Cities and towns