kids encyclopedia robot

King County, Washington facts for kids

Kids Encyclopedia Facts
King County, Washington
Map of Washington highlighting King County
Location in the state of Washington
Map of the USA highlighting Washington
Washington's location in the U.S.
Founded December 22, 1852
Seat Seattle
Largest City Seattle
 - Total
 - Land
 - Water

2,307 sq mi (5,975 km²)
2,116 sq mi (5,480 km²)
191 sq mi (495 km²), 8.3%
 - (2016)
 - Density

983/sq mi (380/km²)
Time zone Pacific: UTC-8/-7
Named for: William Rufus King (1852–2005)
Martin Luther King, Jr. (2005–present)
County flag Flag of King County, Washington
County logo Logo of King County, Washington

King County is a county located in the U.S. state of Washington. As of the 2010 census its population was 1,931,249. King is the most populous county in Washington, and the 13th-most populous in the United States. The county seat is Seattle, which is the state's largest city.

King County is one of three Washington counties that are included in the SeattleTacomaBellevue metropolitan statistical area. (The others are Snohomish County to the north, and Pierce County to the south.) About two-thirds of King County's population lives in the city's suburbs. As of 2011, King County was the 86th highest-income county in the United States.


The county was originally named after William Rufus King who was Vice President when the Washington Territory was created in 1853. In 1986, a motion was introduced to change the namesake to Martin Luther King Jr.

On February 24, 1986, the King County Council passed Council Motion 6461 five votes to four setting forth the historical basis for the renaming of King County in honor of Martin Luther King, Jr. Because only the state can charter counties, this change was not made official until April 19, 2005, when the Governor signed Senate Bill 5332 into law.

The County Council submitted a vote to the public on February 27, 2006 to change the county's logo from a royal crown to an image of King. On March 12, 2007, the new logo was unveiled.

Martin Luther King Jr. visited King County for two days in November 1961.


The county was formed out of territory within Thurston County on December 22, 1852, by the Oregon Territory legislature, and was named after Alabama resident William R. King, who had just been elected Vice President of the United States under President Franklin Pierce. Seattle was made the county seat on January 11, 1853.

King County originally extended to the Olympic Peninsula. According to historian Bill Speidel, when peninsular prohibitionists threatened to shut down Seattle's saloons, Doc Maynard engineered a peninsular independence movement; King County lost what is now Kitsap County, but preserved its entertainment industry.

On February 24, 1986, the King County Council passed Motion 6461 renaming King County to commemorate the Rev. Dr. Martin Luther King, Jr. (1929-1968), the civil rights leader, rather than William Rufus de Vane King (1786-1853), the vice-president-elect for whom the county was named in 1852. The stated reason for the change was the revelation that "William Rufus DeVane King was a slaveowner and a "gentle slave monger" according to John Quincy Adams."


Map of King County

According to the U.S. Census Bureau, the county has a total area of 2,307 square miles (5,980 km2), of which 2,116 square miles (5,480 km2) is land and 191 square miles (490 km2) (8.3%) is water. King County has nearly twice the land area of the state of Rhode Island. The highest point in the county is Mount Daniel at 2,426 meters (7,959 feet) above sea level.

King County borders Snohomish County to the north, Kitsap County to the west, Kittitas County to the east, and Pierce County to the south. It also shares a small border with Chelan County to the northeast. King County includes Vashon Island and Maury Island in Puget Sound.

Geographic features

Granite Mountain King County Washington 2
The Cascade Range (including Granite Mountain shown here) dominates the eastern part of King County.



  • Cedar River
  • Green/Duwamish River
  • Elliott Bay
  • Greenwater River
  • Tolt River
  • Issaquah Creek
  • Lake Sammamish
  • Lake Washington
  • Lake Youngs
  • Lake Union
  • Pratt River
  • Puget Sound
  • Raging River
  • Snoqualmie River
  • Taylor River
  • White River

Major highways

  • I-5 (big).svg Interstate 5
  • I-90 (big).svg Interstate 90
  • I-405 (big).svg Interstate 405
  • US 2.svg U.S. Route 2
  • WA-18.svg State Route 18
  • WA-99.svg State Route 99
  • WA-520.svg State Route 520
  • WA-167.svg State Route 167

Adjacent counties

National protected areas

  • Klondike Gold Rush National Historical Park (part, also in Skagway, Alaska)
  • Snoqualmie National Forest (part)


Historical population
Census Pop.
1860 302
1870 2,120 602.0%
1880 6,910 225.9%
1890 63,989 826.0%
1900 110,053 72.0%
1910 284,638 158.6%
1920 389,273 36.8%
1930 463,517 19.1%
1940 504,980 8.9%
1950 732,992 45.2%
1960 935,014 27.6%
1970 1,156,633 23.7%
1980 1,269,749 9.8%
1990 1,507,319 18.7%
2000 1,737,034 15.2%
2010 1,931,249 11.2%
Est. 2016 2,149,970 11.3%
U.S. Decennial Census
1790–1960 1900–1990
1990–2000 2010–2015

The center of population of the state of Washington in 2010 was located in eastern King County (47°19′51″N 121°37′12″W / 47.330750°N 121.619994°W / 47.330750; -121.619994 (Washington center of population, 2010)). King County's own center of population was located on Mercer Island (47°32′54″N 122°13′48″W / 47.548320°N 122.229983°W / 47.548320; -122.229983 (King County center of population, 2010)).

2010 census

As of the 2010 United States Census, there were 1,931,249 people, 789,232 households, and 461,510 families residing in the county. The population density was 912.9 inhabitants per square mile (352.5/km2). There were 851,261 housing units at an average density of 402.4 per square mile (155.4/km2). The racial makeup of the county was 68.7% White (64.8% Non-Hispanic White), 6.2% African American, 14.6% Asian, 0.8% Pacific Islander, 0.8% Native American, 3.9% from other races, and 5.0% from two or more races. Those of Hispanic or Latino origin made up 8.9% of the population. In terms of ancestry, 17.1% were German, 11.6% were English, 11.1% were Irish, 5.5% were Norwegian, and 2.9% were American.

Of the 789,232 households, 29.2% had children under the age of 18 living with them, 45.3% were married couples living together, 9.1% had a female householder with no husband present, 41.5% were non-families, and 31.0% of all households were made up of individuals. The average household size was 2.40 and the average family size was 3.05. The median age was 37.1 years.

The median income for a household in the county was $68,065 and the median income for a family was $87,010. Males had a median income of $62,373 versus $45,761 for females. The per capita income for the county was $38,211. About 6.4% of families and 10.2% of the population were below the poverty line, including 12.5% of those under age 18 and 8.6% of those age 65 or over.


See also: Category:Cities in King County, Washington



Census-designated places

Other unincorporated communities

Ghost towns

Images for kids

kids search engine
King County, Washington Facts for Kids. Kiddle Encyclopedia.