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 2026 the population of King County is 2,396,522. The population is expected to grow to 2,484,872 by 2031 - a growth rate of 0.73%.
The median age of King County residents is 38.
The diversity index of King County is 72.7, meaning that there is a 73% 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 $196,215 and projected to be $223,692 in 2031. Per capita income is $80,110, projected to be $91,590 in 2031. 13.93% of households – 333,748 – have an income of $200,000 or higher. Average net worth is $2,054,360 and the average disposable income is $143,783.
There are 1,033,922 housing units in King County; 518,680 are owner-occupied, 457,559 are rented, and 57,683 are vacant. The average home value is $1,096,903, with 163,527 homes built in 2010 or later, and 109,564 built in 1939 or earlier.
1,159,654 residents both live and work in/around King County. The average travel time is 27.6 minutes. 1.45% people have a commute of less than 5 minutes while 1.35% commute 90 minutes or more each way. Of commuters, 618,912 drive alone, 86,153 carpool, and 83,585 take public transportation. 79,694 use other modes of transport such as motorcycle, bicycle, walking, etc. 358,401 residents work from home.
237,539 members of the workforce hold a high school diploma or GED. 148,175 have associates degrees, 575,733 have bachelor’s degrees, and 445,977 hold a graduate or professional degree.
Source: ESRI, 2026-08-31
