Overview
King County is home to 2,262,713 people (Census ACS 5-Year, 2023), making it larger than all but a handful of U.S. counties. It's Washington's most populous county by a wide margin, ranking higher than 97% of counties in the state on population alone. Seattle sits at its center, and the county stretches from Puget Sound east into the Cascade foothills.
The numbers that define King County cluster at the extremes. Median household income hits $122,148 (Census ACS 5-Year, 2023), higher than 99% of U.S. counties. Median home values reach $811,200 (Census ACS 5-Year, 2023), also in the top 1%. Education levels match: 55.9% of adults hold a bachelor's degree or higher (Census ACS 5-Year, 2023), a rate that outpaces nearly every county in the country.
The median age is 37.3 (Census ACS 5-Year, 2023). That's younger than about 83% of U.S. counties. A large, young, highly educated, high-earning population, concentrated in one of the most expensive housing markets in the country. Those facts shape nearly everything else in the data.
Demographics
King County skews young compared to most of the U.S. At a median age of 37.3 (Census ACS 5-Year, 2023), it sits lower than roughly 83% of counties nationally. That's consistent with what you'd expect from a major metro with a large tech sector drawing working-age residents.
Education attainment is unusually high. More than half the adult population, 55.9%, holds at least a bachelor's degree (Census ACS 5-Year, 2023). That's higher than 99% of U.S. counties and 97% of Washington counties. Few places in the country match that concentration of college-educated workers.
The county's racial composition reflects its role as an urban, international hub. White residents make up 54.3% of the population (Census ACS 5-Year, 2023), which is lower than about 84% of U.S. counties. Asian residents account for 19.8%, a share higher than 99% of counties nationally. Hispanic residents make up 10.8%, Black residents 6.4%, and Native residents 0.4% (Census ACS 5-Year, 2023). That diversity index is one of the highest in the Pacific Northwest.
The 320,430 Social Security beneficiaries (SSA OASDI, 2024) represent about 14% of the total population, well below the national share. That aligns with the younger median age: fewer retirees relative to the working population.
Education
King County's public schools spend $21,003 per pupil (Education Data Portal, 2020). The national average hovers around $15,000, so King County runs about 40% above that mark. Total enrollment reaches 266,847 students (Education Data Portal, 2021), reflecting the county's population size.
The student-teacher ratio sits at 18.4 to 1 (Education Data Portal, 2021). That's higher than the national average of roughly 15.5 to 1 and ranks above 93% of U.S. counties. More students per teacher, despite the high spending. That gap points to where the money goes: higher teacher salaries driven by cost of living, not necessarily smaller class sizes.
Graduation rates tell a more complicated story. At 81.3% (Education Data Portal, 2019), King County falls below the national average of about 87%. It ranks lower than roughly 80% of U.S. counties on this metric. For a county that leads the nation in adult education attainment, that's a notable disconnect. Part of the explanation may lie in how large, diverse urban districts measure completion differently, and part may reflect real gaps in outcomes across income levels within the county.
Economy & Employment
The labor force in King County totals 1,367,599 people, with 1,301,180 employed (BLS LAUS, 2025). The unemployment rate is 4.9% (BLS LAUS, 2025), which sits higher than about 79% of U.S. counties. For a county this wealthy, that rate deserves attention, though it partly reflects the sheer size of the labor force and the natural churn in a tech-heavy economy.
Income numbers are where King County separates from the pack. Median household income of $122,148 (Census ACS 5-Year, 2023) ranks higher than 99% of counties nationally. Per capita income reaches $71,062 (Census ACS 5-Year, 2023), also in the top 1%. IRS data shows an average adjusted gross income of $180,334 per return (IRS Statistics of Income, 2021), with total AGI across the county topping $205.7 billion from 1,140,760 returns. That tax base is enormous.
The poverty rate is 8.3% (Census ACS 5-Year, 2023), lower than about 85% of U.S. counties. In absolute terms, though, 8.3% of 2.26 million people means roughly 188,000 residents live below the poverty line. High incomes at the top can obscure what's happening at the bottom. And in a county where median rent exceeds $2,000 a month, that 8.3% likely understates financial strain for households earning just above the threshold.
The mean commute is 20.8 minutes (Census ACS 5-Year, 2023), shorter than about 62% of U.S. counties. For a metro of this size, that's relatively low, likely reflecting the concentration of jobs within Seattle proper and surrounding employment centers.
Housing & Cost of Living
Median home value in King County is $811,200 (Census ACS 5-Year, 2023). That's higher than 99% of U.S. counties and 97% of Washington counties. At roughly 6.6 times the median household income, the price-to-income ratio is steep, even by major metro standards.
Median gross rent runs $2,035 per month (Census ACS 5-Year, 2023), also higher than 99% of counties nationally. A household earning the median income would spend about 20% of gross pay on rent at that level, which stays within traditional affordability guidelines. But a household earning half the median would hit 40%, well into cost-burdened territory.
The county has 988,330 total housing units, with 60,513 vacant (Census ACS 5-Year, 2023). That's a vacancy rate of 6.1%, lower than roughly 91% of U.S. counties. Tight supply in an expensive market. HUD Fair Market Rent data for 2026 is available for the county but specific bedroom-level breakdowns weren't included in this dataset.
The combination of high home values, high rents, and low vacancy rates describes a market with persistent demand pressure. For a potential buyer at the median income level, a conventional mortgage on an $811,200 home would require a down payment north of $160,000 and monthly payments that eat significantly into take-home pay, even at that $122,148 median income.
Health & Wellness
King County's health metrics paint a mixed picture, though one that generally looks favorable compared to the rest of the country.
Obesity rates sit at 22.4% (CDC PLACES, 2023), lower than nearly every U.S. county. Diabetes prevalence is 7.2% (CDC PLACES, 2023), also lower than about 99% of counties nationally. High blood pressure affects 26.2% of residents (CDC PLACES, 2023), a rate lower than roughly 98% of counties. These chronic disease numbers consistently rank near the bottom of national distributions, which in health terms means near the best.
Cholesterol screening stands at 85.4% (CDC PLACES, 2023), higher than 86% of counties nationally. Annual checkup rates, however, are only 69.9% (CDC PLACES, 2023), lower than about 91% of counties. Residents are getting screened but not necessarily doing routine visits.
Mental health data shows 14.7% reporting frequent poor mental health days and 23.4% reporting depression (CDC PLACES, 2023). The poor mental health rate is lower than 98% of counties nationally. Depression sits at the 44th national ranking, roughly in the middle. Poor physical health days are reported by 9.6% of residents (CDC PLACES, 2023), lower than virtually all U.S. counties.
The uninsured rate is 6.8% (CDC PLACES, 2023), lower than about 95% of counties. Washington's Medicaid expansion and the county's high rate of employer-sponsored coverage through the tech sector help keep that number down.
Climate & Natural Disasters
King County is one of the wettest counties in the country. Annual precipitation averages 67.4 inches (NOAA Climate Data Online, 2025), more than 99% of U.S. counties. That moisture comes mostly as rain: annual snowfall is just 4.8 inches (NOAA, 2025), putting the county in the bottom quarter for snow nationally. Average temperatures run mild year-round, with a mean of 48.9°F, a typical high of 55.1°F, and a typical low of 41.7°F (NOAA, 2025).
The rain is persistent, not dramatic. What creates real risk here is the combination of saturated terrain and aging infrastructure when storms stack up.
FEMA has declared 34 disasters in the county going back to 1964 (FEMA OpenFEMA, 2026), more than 92% of U.S. counties. Floods dominate the record, appearing in roughly half of all declarations. Severe storms account for most of the rest. The most recent declaration came in December 2025, a flood emergency. Before that, a severe storm major disaster in April 2024.
A few entries stand out beyond the recurring flood-and-storm pattern. The county was included in Washington's 2001 earthquake declaration following the Nisqually quake, and in the 1980 volcanic eruption declaration after Mount St. Helens. Both serve as reminders that the Pacific Northwest hazard picture extends beyond rain. COVID-19 generated two separate federal declarations in March 2020, one emergency and one major disaster.
The frequency is the real story: 34 declarations over roughly six decades works out to more than one every two years on average. For residents and property owners, that history shapes what to expect from insurance markets, infrastructure investment, and emergency preparedness planning going forward.
Financial Profile
IRS data from 2021 shows 1,140,760 tax returns filed in King County, with a total adjusted gross income of $205.7 billion (IRS Statistics of Income, 2021). Average AGI per return was $180,334, and average total income was $181,500. Both figures rank higher than 99% of U.S. counties.
The gap between average AGI ($180,334) and median household income ($122,148) tells a familiar story about income distribution. A long right tail of very high earners pulls the average well above the median. In King County's case, that gap of about $58,000 reflects the concentration of tech wealth and executive compensation.
Banking access is solid. The FDIC counts 287 bank branches in the county holding $25.9 billion in total deposits (FDIC Summary of Deposits, 2023). That branch count ranks higher than 98% of counties nationally. On a per-capita basis, it works out to roughly one branch per 7,900 residents, which is typical for dense urban areas where digital banking has reduced the need for physical locations.
Social Security beneficiaries total 320,430 (SSA OASDI, 2024). That's a large number in absolute terms, ranking higher than 99% of counties, but relative to the 2.26 million population, the share is modest. The younger workforce tilts the ratio.
Key Comparisons
King County sits at the far end of most national distributions. Here's how it stacks up.
Income and wealth. Median household income of $122,148 (Census ACS 5-Year, 2023) is higher than 99% of U.S. counties and 97% of Washington counties. Per capita income of $71,062 follows the same pattern. Average AGI of $180,334 (IRS Statistics of Income, 2021) reinforces the picture: this is one of the wealthiest counties in the country by virtually any income measure.
Housing costs. At $811,200, the median home value (Census ACS 5-Year, 2023) is higher than 99% of counties nationally. Median rent of $2,035 matches. The vacancy rate of 6.1% is lower than 91% of counties. High prices, tight supply.
Education. The 55.9% bachelor's attainment rate (Census ACS 5-Year, 2023) ranks higher than 99% of counties. Per-pupil spending of $21,003 (Education Data Portal, 2020) exceeds the national average by about 40%. But the graduation rate of 81.3% (Education Data Portal, 2019) falls below most counties.
Health. Obesity at 22.4%, diabetes at 7.2%, and high blood pressure at 26.2% (CDC PLACES, 2023) all rank among the lowest in the country. The uninsured rate of 6.8% is lower than 95% of counties. Physical health metrics are similarly strong.
Demographics. The median age of 37.3 is younger than 83% of counties. The Asian population share of 19.8% is higher than 99% of counties. The poverty rate of 8.3% is lower than 85% of counties.
Disaster exposure. With 34 FEMA declarations (FEMA OpenFEMA, 2026), King County has experienced more disasters than 92% of U.S. counties.
Within Washington, King County leads on income, home values, education, and population. It ranks near the bottom of the state on health metrics (in a good way) and near the middle on climate and commute times. The county that drives Washington's economy also concentrates its affordability pressures.
Data Sources
- Census ACS 5-Year, 2023: Population, income, housing, demographics, education attainment, commute times, poverty rate, vacancy rate
- BLS LAUS, 2025: Unemployment rate, employment count, labor force
- CDC PLACES, 2023: Health metrics including obesity, diabetes, blood pressure, depression, insurance coverage, checkup rates, physical and mental health
- HUD Fair Market Rents, 2026: Fair market rent data (bedroom-level breakdowns not available in this dataset)
- FEMA OpenFEMA, 2026: Disaster declarations and history
- IRS Statistics of Income, 2021: Tax returns, adjusted gross income, total income
- FDIC Summary of Deposits, 2023: Bank branch count and total deposits
- NOAA Climate Data Online, 2025: Temperature and precipitation data
- SSA OASDI, 2024: Social Security beneficiaries
- Education Data Portal, 2019-2021: Per-pupil spending, enrollment, student-teacher ratio, graduation rate
- USDA Census of Agriculture: No data available for King County