Counties in Washington by population, 2025
King County had the highest population of 39 counties in 2025, at 2.34 million. Garfield County had the lowest, at 2,416. The median was 71,165 and the figure for Washington was 8 million. Source: the U.S. Census Bureau.
All counties, 2025
Full ranking
Other periods
About this ranking
Resident population. Spain and the EU: 1 January, with Spanish figures from the official municipal register (Padrón). United States: Census Bureau population estimates for 1 July. Other countries and the World: World Bank mid-year estimates, which count all residents regardless of legal status or citizenship.
For Denmark, Statistics Denmark counts the registered resident population on 1 January. Greenland and the Faroe Islands are excluded. The annual series selects the first-quarter reference date from FOLK1A. The World Bank series exists for every country, so use it (through compare) to rank countries on one basis.
Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. Equal values share a rank.
How to cite
U.S. Census Bureau. Annual estimates of the resident population for the United States, states and counties, 1 July (Population Estimates Program). https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/. Retrieved 2026-10-08.Use this data in your AI agent
Invokely serves this figure to AI assistants through MCP and to code through a REST API, with the source and citation attached. Ask your assistant:
Rank Counties in Washington by population using official data, and cite the source.
rank_places {"indicator":"population","level":"province","within":"Washington","limit":10}
GET https://invokely.ai/api/v1/rank?indicator=population&level=province&within=Washington&limit=10Questions
Which county has the highest population?
King County, with 2.34 million in 2025, according to the U.S. Census Bureau.
Which county has the lowest population?
Garfield County, with 2,416 in 2025.
Where does this ranking come from?
Every value comes from one source and one period, so the places are comparable: U.S. Census Bureau, Annual estimates of the resident population for the United States, states and counties, 1 July (Population Estimates Program). Retrieved 2026-10-08.
Population: other rankings
- Countries
- EU countries
- US states
- EU regions (NUTS 2)
- US counties
- Autonomous communities of Spain
- Provinces of Spain
- Municipalities of Spain
- Regions of Germany (NUTS 2)
- Regions of France (NUTS 2)
- Regions of Italy (NUTS 2)
- Regions of Poland (NUTS 2)
Counties in Washington: more rankings
- Asian population share
- Bachelor's degree or higher, population 25 and over
- Live births, July to June
- Black or African American population share
- Crude birth rate, July to June
- Crude death rate, July to June
- Deaths, July to June
- Foreign-born population share
- Real GDP growth
- GDP per capita, US dollars
- Gross domestic product (GDP), US dollars
- Hispanic or Latino population share
- Homeownership rate (US, housing units)
- Median age
- Median gross rent (monthly)
- Median home value