Association of Washington State Public Facilities District - Member Directory

King County is a county located in the U.S. state of Washington. The population was 2,269,675 in the 2020 census,[1] making it the most populous county in Washington, and the 12th-most populous in the United States. The county seat is Seattle,[2] also the state’s most populous city.

Originally named after US representative, senator, and then vice president-elect William R. King in 1852, the county government amended its designation in 1986 to honor Martin Luther King Jr., a prominent activist and leader during the civil rights movement. The change was approved by the state government in 2005.

It is one of three Washington counties that are included in the Seattle–Tacoma–Bellevue metropolitan statistical area along with Snohomish County to the north and Pierce County to the south. About two-thirds of King County’s population lives in Seattle’s suburbs, which largely developed in the late 20th century and early 21st century as bedroom communities before becoming job centers for the technology industry.[3]