County Maps US

King County, Washington

The most populous of Washington's 39 counties.

CountyFIPS 53033

Within Washington
King County, highlighted, with the areas around it. Boundaries generalised from the 2025 Census cartographic boundary file; neighbour fills carry no data. The dot marks Seattle, the county seat, located via the 2025 Census Gazetteer.

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Population
2,344,939
+70,635 (+3.1%) since 2020
Land area
2,116
square miles. A further 8.3% of the total area is water
Population density
1,108
people per square mile, computed rather than published
County seat
Seattle
Seat of county government.
Established
1852
173 years ago
Largest city
Seattle city
Population 784,777.

Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025; Wikidata (CC0), Wikidata. Retrieved 30 August 2026.

Satellite view

Aerial imagery of King County with its boundary drawn on top. A map shows you the shape; this shows you what is inside it, and which side of the line a place falls on.

Aerial view of King County, Washington from the USGS National Map, with its boundary outlined
Imagery: USGS National Map, USGS Imagery Only, public domain, requested from USGS by your browser when you reach this point on the page, at 800 by 588 pixels. The boundary is the 2025 Census cartographic boundary file, reprojected to Web Mercator to match the imagery. You can also open the USGS National Map viewer.

Where King County ranks

Position among the 39 counties of Washington, and among all 3,144 US counties and county-equivalents. Computed from the figures on this page.

MeasureValueIn WashingtonNationally
Population2,344,9391st of 3913th of 3,144
Land area2,116 sq mi11th of 39264th of 3,144
Population density1,108 per sq mi1st of 39147th of 3,144
Median household income$124,7461st of 3944th of 3,143

Full data for King County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population2,344,939Vintage 2025 Population Estimates
Population in 20202,274,304Vintage 2025 Population Estimates
2020 estimates base?2,269,668Vintage 2025 Population Estimates
Land area2,116 sq mi2025 Gazetteer Files
Water area191.7 sq mi2025 Gazetteer Files
Total area2,307 sq mi2025 Gazetteer Files
Population density?1,108 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$124,746American Community Survey 2020-2024 5-Year Estimates
Median home value$859,900American Community Survey 2020-2024 5-Year Estimates
Median age37.4American Community Survey 2020-2024 5-Year Estimates
Households941,054American Community Survey 2020-2024 5-Year Estimates
Housing units1,003,284American Community Survey 2020-2024 5-Year Estimates

Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025; US Census Bureau, American Community Survey, American Community Survey 2020-2024 5-Year Estimates, released 29 January 2026. Population density is computed here, not published: it divides the Vintage 2025 population estimate by the 2025 Gazetteer land area, which are two different Census products. Retrieved 30 August 2026.

How the population changed

The Census Bureau publishes the components behind an estimate, not just the total. For the year to July 2025:

Births minus deaths
+7,424
22,770 births, 15,346 deaths
Net migration
+19,349
More people moved in than moved out.

Source: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026. Retrieved 30 August 2026.

The 6 areas bordering King County

Ordered by the length of the border actually shared, which the Census Bureau publishes in its county adjacency file and which no other county reference presents.

Bordering areaStateShared borderPopulation
Pierce CountyWashington78 mi946,288
Kittitas CountyWashington69 mi48,803
Snohomish CountyWashington62 mi870,656
Kitsap CountyWashington28 mi283,374
Chelan CountyWashington18 mi81,941
Yakima CountyWashington115 ft259,185

Source: US Census Bureau, County Adjacency File, 2025 County Adjacency File, released 15 September 2025. Retrieved 30 August 2026.

Side by side

All 39 counties of Washington

Open the interactive Washington county map, or jump straight to any of them.

Data on this page last rebuilt 30 August 2026. How these figures are produced.