King County vs Pierce County
Two neighbouring counties in Washington, compared on population, size, income and housing. They share 78 mi of border.
King County
Washington
Pierce County
Washington
Both outlines are drawn at true relative size. King County spans about 117.7 km at its widest.
Side by side
| Measure | King County | Difference | Pierce County |
|---|---|---|---|
| Population | 2,344,939 | +147.8% | 946,288 |
| Change since 2020 | 3.1% | +0.6 pp | 2.5% |
| Land area | 2,116 sq mi | +26.8% | 1,668 sq mi |
| Population density | 1,108 per sq mi | +95.4% | 567 per sq mi |
| Median household income | $124,746 | +25.3% | $99,564 |
| Median home value | $859,900 | +63.3% | $526,600 |
| Median age | 37.4 | +1.1% | 37.0 |
| Households | 941,054 | +167.9% | 351,330 |
| Housing units | 1,003,284 | +171.4% | 369,709 |
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; US Census Bureau, County Adjacency File, 2025 County Adjacency File, released 15 September 2025. The difference column is computed here: the first county's figure against the second, expressed as a percentage of the second. The change-since-2020 row is the exception: two growth rates differ in percentage points (pp), not percent. Retrieved 30 August 2026.
What the numbers say
- King County holds about 2.5 times the population of Pierce County: 2,344,939 against 946,288.
- King County covers more ground, at 2,116 square miles against 1,668.
- King County is the more crowded of the two, at 1,108 people per square mile against 567.
- Median household income is higher in King County, by 25,182 dollars a year.
- Since 2020, King County has grown by 3.1% and Pierce County has grown by 2.5%.
- They share 78 mi of common border, which the Census Bureau publishes in its county adjacency file and which almost no other county reference presents.
Full pages
Want a different pair? Compare any two of the 3,144 US counties.
Rebuilt from source data 30 August 2026. How these figures are produced.