King County spans an impressive 2,128 square miles and boasts an estimated population exceeding 2.2 million, making it the state's most populous county. Seattle is the county's largest city. Additionally, King County features a rich tapestry of cities such as Bellevue, Kent, Renton, Auburn, Redmond, and Tukwila, each contributing to the area's dynamic and thriving community.
As of 2025 the population of King County is 2,366,841. The population is expected to grow to 2,447,741 by 2030 - a growth rate of 0.67%.
The median age of King County residents is 38.
The diversity index of King County is 72.3, meaning that there is a 72% chance that any two people selected out of 100 residents will be of different race or ethnicity from one another.
The average household income in King County is $187,096 and projected to be $210,946 in 2030. Per capita income is $75,636, projected to be $85,146 in 2030. 13.08% of households – 309,692 – have an income of $200,000 or higher. Average net worth is $1,891,929 and the average disposable income is $139,703.
There are 1,011,562 housing units in King County; 519,500 are owner-occupied, 436,592 are rented, and 55,470 are vacant. The average home value is $1,084,876, with 144,562 homes built in 2010 or later, and 109,135 built in 1939 or earlier.
1,148,670 residents both live and work in/around King County. The average travel time is 28.1 minutes. 1.49% people have a commute of less than 5 minutes while 1.49% commute 90 minutes or more each way. Of commuters, 631,878 drive alone, 88,155 carpool, and 97,519 take public transportation. 79,915 use other modes of transport such as motorcycle, bicycle, walking, etc. 319,205 residents work from home.
243,173 members of the workforce hold a high school diploma or GED. 135,575 have associates degrees, 576,844 have bachelor’s degrees, and 428,328 hold a graduate or professional degree.
