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Multnomah County, Oregon facts for kids

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Multnomah County
Portland panorama3.jpg
Mt. Hood (Multnomah County, Oregon scenic images) (mulDA0006).jpg
Portland, OR — St. John's Bridge, view of east tower from southwest.jpg
Arlene Schnitzer Concert Hall.jpg
First Presbyterian Church - Portland Oregon.jpg
Vista House.jpg
Spillway, Bonneville Dam-2.jpg
Official seal of Multnomah County
Official logo of Multnomah County
Map of Oregon highlighting Multnomah County
Location within the U.S. state of Oregon
Map of the United States highlighting Oregon
Oregon's location within the U.S.
Country  United States
State  Oregon
Founded December 22, 1854
Seat Portland
Largest city Portland
 • Total 466 sq mi (1,210 km2)
 • Land 431 sq mi (1,120 km2)
 • Water 34 sq mi (90 km2)  7.4%%
 • Total 815,428
 • Estimate 
803,377 Decrease
 • Density 1,874/sq mi (724/km2)
Time zone UTC−8 (Pacific)
 • Summer (DST) UTC−7 (PDT)
Congressional districts 1st, 3rd, 5th

Multnomah County is one of the 36 counties in the U.S. state of Oregon. As of the 2020 census, the county's population was 815,428. Multnomah County is part of the PortlandVancouverHillsboro, OR–WA Metropolitan Statistical Area. Though smallest in area, Multnomah County is the state's most populous county. Its county seat, Portland, is the state's largest city.


Multnomah County (the thirteenth in Oregon Territory) was created on December 22, 1854, formed out of two other Oregon counties – the eastern part of Washington County and the northern part of Clackamas County. Its creation was a result of a petition earlier that year by businessmen in Portland complaining of the inconvenient location of the Washington County seat in Hillsboro and of the share of Portland tax revenues leaving the city to support Washington County farmers. County commissioners met for the first time on January 17, 1855. The county is named after the Chinook word for the "lower river", Multnomah and Matlnomaq being alternative, interpretive English spellings of the same word. In Chinook Jargon, Ne-matlnomaq, means the "place of matlnomaq" or the (singular) Ne-matlnomag, "the lower river", from the Oregon City Falls to the Columbia river. The explorer William Clark wrote in his Journal: "I entered this river...called Multnomah...from a nation who reside on Wappato Island, a little below the enterence" (quoted from Willamette Landings by H.M. Corning). Note that Clark refers to Sauvies Island as Wappato Island and the lower Willamette River as Multnomah. Simply put, Multnomah or "down river" is the shortened form of nematlnomaq, meaning "the down river".

In 1924, the county's three commissioners were indicted and recalled by voters "in response to 'gross irregularities' in the award of contracts for construction of the Burnside and Ross Island bridges"; since all three had been supported by the Ku Klux Klan, their recall also helped reduce that organization's influence in the city.

Vanport, built north of Portland in 1943 to house workers for Kaiser Shipyards, was destroyed by a flood five years later.

In 1968, the Oregon Legislative Assembly referred a bill, Ballot Measure 5, to voters that would amend the state constitution to allow for consolidated city-county governments when the population is over 300,000. The 1968 voters' pamphlet noted that Multnomah County would be the only county in Oregon affected by the measure and voters approved the referendum in the 1968 general election. Since the approval of Measure 5 in 1968, an initiative to merge the county with Portland has been considered and placed on the county ballot several times. The merger would have formed a consolidated city-county government like that of San Francisco, California. None of these proposals has been approved.

Since 2000

In the 2000 presidential election, Multnomah played a decisive role in determining the winner of the state's electoral votes. Al Gore carried the county by more than 104,000 votes, enough to offset the nearly 100,000-vote advantage that George W. Bush had earned among Oregon's 35 other counties.

In February 2001, the Multnomah County Board of Commissioners unanimously accepted the recommendation of the Library Advisory Board and authorized the library to enter into a lawsuit to stop the Children's Internet Protection Act. The US Supreme Court ultimately decided in 2003 that the law was constitutional in US v. ALA. However, the library chose to turn down $104,000 per year of federal funding under CIPA to be able to continue to offer unfiltered Internet access.

Faced with decreasing government revenues due to a recession in the local economy, voters approved a three-year local income tax (Measure 26-48) on May 20, 2003 to prevent further cuts in schools, police protection, and social services. Multnomah County was one of the few local governments in Oregon to approve such a tax increase.

On March 2, 2004, Multnomah County Chair Diane Linn announced the county would begin granting licenses for same-sex marriages, pursuant to a legal opinion issued by its attorney deeming such marriages lawful under Oregon law. Her announcement was supported by three other commissioners (Serena Cruz, Lisa Naito, Maria Rojo de Steffey), but criticized by Lonnie Roberts, who represents the eastern part of Multnomah county and was left out of the decision. Within a few days, several groups joined to file a lawsuit to halt the county's action.

But after that, Linn and the three commissioners developed a public feud, with the latter becoming known as the "mean girls". The county government has also faced significant budget issues, including not being able to open the Wapato Corrections Facility since it was built in 2003.


According to the U.S. Census Bureau, the county has a total area of 466 square miles (1,210 km2), of which 431 square miles (1,120 km2) is land and 34 square miles (88 km2) (7.4%) is water. It is the smallest county in Oregon by area. It is located along the south side of the Columbia River.

The county includes a number of extinct volcanoes in the Boring Lava Field. The Oregon side of the Columbia River Gorge forms the eastern portion of the county's northern border.

Major highways

  • I-5
  • I-84
  • I-205
  • I-405
  • US 26
  • US 30

  • US 30 Byp.
  • US 99 (decommissioned)
  • OR 10
  • OR 43
  • OR 120
  • OR 213

Adjacent counties

National protected area

  • Mount Hood National Forest (part)


Historical population
Census Pop.
1860 4,150
1870 11,510 177.3%
1880 25,203 119.0%
1890 74,884 197.1%
1900 103,167 37.8%
1910 226,261 119.3%
1920 275,898 21.9%
1930 338,241 22.6%
1940 355,099 5.0%
1950 471,537 32.8%
1960 522,813 10.9%
1970 556,667 6.5%
1980 562,640 1.1%
1990 583,887 3.8%
2000 660,486 13.1%
2010 735,334 11.3%
2020 815,428 10.9%
2021 (est.) 803,377 9.3%
U.S. Decennial Census
1790-1960 1900-1990
1990-2000 2010-2020

Racial and ethnic composition since 1960

Racial composition 2020 2010 2000 1990 1980 1970 1960
White (non-Hispanic) 65.7% 72.1% 76.5% 85.3% 88.4% - -
Hispanic or Latino 12.7% 10.9% 7.5% 3.1% 2.0% 1.5% -
Asian (non-Hispanic) 7.5% 6.5% 5.7% 4.6% - - 1.2%
Black or African American (non-Hispanic) 5.4% 5.4% 5.6% 6.0% 5.3% 3.9% 3.0%
Native American (non-Hispanic) 0.7% 0.8% 1.0% 1.1% - - 0.2%
Pacific Islander (non-Hispanic) 0.7% 0.5% 0.3% - - - -
Mixed race (non-Hispanic) 6.8% 3.6% 4.0% - - - -

2010 census

As of the 2010 census, there were 735,334 people, 304,540 households, and 163,539 families residing in the county. The population density was 1,704.9 inhabitants per square mile (658.3/km2). There were 324,832 housing units at an average density of 753.2 per square mile (290.8/km2). The racial makeup of the county was 76.5% white, 6.5% Asian, 5.6% black or African American, 1.1% American Indian, 0.5% Pacific islander, 5.1% from other races, and 4.6% from two or more races. Those of Hispanic or Latino origin made up 10.9% of the population. In terms of ancestry, 19.4% were German, 12.2% were Irish, 11.4% were English, and 4.2% were American.

Of the 304,540 households, 27.0% had children under the age of 18 living with them, 38.6% were married couples living together, 10.7% had a female householder with no husband present, 46.3% were non-families, and 32.6% of all households were made up of individuals. The average household size was 2.35 and the average family size was 3.03. The median age was 35.7 years.

The median income for a household in the county was $49,618 and the median income for a family was $62,956. Males had a median income of $45,152 versus $38,211 for females. The per capita income for the county was $28,883. About 11.3% of families and 16.0% of the population were below the poverty line, including 21.1% of those under age 18 and 12.1% of those age 65 or over.



Unincorporated communities

Former communities


The principal industries of Multnomah County are manufacturing, transportation, wholesale and retail trade, and tourism. Since Oregon does not have a sales tax, it attracts shoppers from southwest Washington.

The Port of Portland, established in 1891 and combined with the City of Portland's Commission of Public Docks in 1971, ranks third in total waterborne commerce on the West Coast, and 31st in the nation for total tonnage according to the 2009 American Association of Port Authorities' Port Industries Statistics. Portland is one of the five largest auto import ports in the nation and is the West Coast's leading exporter of grain and lumber. The Port of Portland is also responsible for Portland International Airport (PDX) in the northeast section of Portland, the Troutdale Airport a few miles east of PDX in Multnomah County, the Hillsboro Airport to the west in Washington County, and Mulino State Airport to the south in Clackamas County.

Out of the 199 cities and counties located in the five West Coast states, Multnomah County ranked 198th in private sector job creation from 1997 to 2009.


The county is home to a number of Portland-area attractions and venues, including Oregon Museum of Science and Industry, Portland Art Museum, Memorial Coliseum, Oregon Convention Center, Moda Center, Providence Park, Washington Park, Oregon Zoo, International Rose Test Garden, Lan Su Chinese Garden, Portland Japanese Garden, Hoyt Arboretum and Pittock Mansion.

It is also home to the Historic Columbia River Highway, Multnomah Falls, and Oxbow Regional Park.

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