Mercer Island, Washington Demographics & Population 2026
During the 2020–2024 ACS period, Mercer Island, Washington had a total population of 25,307, the 52nd largest city in Washington, with a median household income of $219,069, which is 123% higher than the state average. The poverty rate is 3.8%.
Data vintage: U.S. Census Bureau ACS 2020–2024 5-Year Estimates · refreshed July 2026 · Methodology & source notes
Key Takeaways
- Household income is 123% above the state average — one of the wealthiest communities in Washington.
- An exceptionally low poverty rate of 3.8% — among the lowest in Washington.
- 81.5% of adults hold a bachelor's degree or higher — top 10% in Washington.
- Housing affordability is a challenge — homes cost 9.1x the median household income.
Mercer Island Quick Facts
How Mercer Island Changed
Change from the 2019–2023 ACS period to 2020–2024. These are rolling five-year estimates, not year-over-year measurements.
| Metric | 2019–2023 | 2020–2024 | Change |
|---|---|---|---|
| Population | 25,282 | 25,307 | +0.1% |
| Median household income | $202,359 | $219,069 | +8.3% |
| Median home value | $1,884,200 | $2,000,000+ | +6.1% |
How Mercer Island Compares
Median Household Income
Median Home Value
Economy & Housing
Household Income Distribution
Detailed income brackets
Employment
Housing Overview
People & Demographics
Age Distribution
Race & Ethnicity
Diversity Index
Moderate diversity with one or two groups making up the majority.
State average: 56 | National average: 61
Education
Educational Attainment (Adults 25+)
Mercer Island Rankings in Washington
Explore Washington Rankings
Other Cities in King County
| City | Population | Median Income | Poverty | Home Value |
|---|---|---|---|---|
| Seattle | 754,195 | $123,860 | 9.9% | $938,600 |
| Bellevue | 151,847 | $165,576 | 7.2% | $1,340,300 |
| Kent | 135,603 | $92,302 | 10.8% | $587,800 |
| Renton | 105,317 | $100,432 | 8.1% | $672,600 |
| Federal Way | 99,493 | $86,909 | 13.0% | $552,800 |
| Kirkland | 92,621 | $150,414 | 6.1% | $1,115,400 |
| Auburn | 85,676 | $97,884 | 8.9% | $547,900 |
| Redmond | 77,353 | $162,560 | 5.6% | $1,167,800 |
| Sammamish | 66,463 | $239,690 | 4.3% | $1,407,300 |
| Shoreline | 61,431 | $112,751 | 8.8% | $811,100 |
Cities Similar to Mercer Island
These cities in the same state have comparable population and economic profiles.
| City | Population | Median Income | Home Value | Bachelor's+ | Poverty |
|---|---|---|---|---|---|
| Mill Creek East | 25,453 | $192,937 | $905,400 | 67.6% | 4.1% |
| Cottage Lake | 22,518 | $213,106 | $1,230,700 | 67.8% | 3.2% |
| Bainbridge Island | 24,631 | $172,188 | $1,155,900 | 76.4% | 3.5% |
| Union Hill-Novelty Hill | 23,047 | $185,369 | $1,218,500 | 71.7% | 5.7% |
| Silver Firs | 22,306 | $163,418 | $859,900 | 51.9% | 5.9% |
Population Overview
Mercer Island is a mid-sized community located in Washington, within King County. The total population is 25,307. It ranks as the 52nd most populous out of 628 Census-designated places in Washington.
Age Demographics
The median age in Mercer Island is 46.4 years. This is 21% higher than the state median of 38.3 years. 11.6% of residents are 75 or older, suggesting a significant retirement-age population with implications for healthcare services and senior housing.
Economy, Income & Housing
The median household income in Mercer Island is $219,069. This is 123% higher than the state median of $98,141. It is also 171% higher than the national median of $80,734. The poverty rate stands at 3.8%. This is 62% lower than the state poverty rate of 9.9%. This exceptionally low poverty rate indicates strong economic prosperity across the community. The unemployment rate is 3.0%. This is 40% lower than the state rate of 5.1%. The median home value is $2,000,000+. Housing costs are 254% higher than the state median of $564,600. The home-value-to-income ratio of 9.1x suggests that housing affordability is a significant concern for many residents. 67.0% of occupied housing units are owner-occupied. This homeownership rate is 5% higher than the state average of 63.8%.
Race & Ethnicity
The largest racial or ethnic group in Mercer Island is White (non-Hispanic), making up 63.3% of the population. Asian residents account for 24.4%. The Black or African American population (0.9%) is well below the state average of 3.9%. The Hispanic or Latino population (2.4%) is well below the state average of 14.4%. The Asian population is significantly higher than the state average (24.4% vs 9.7%).
Education
81.5% of residents aged 25 and older hold a bachelor's degree or higher. This places Mercer Island in the top 10% of all cities in the state for educational attainment. This is 106% higher than the state rate of 39.6%. Nationally, 35.7% of adults hold at least a bachelor's degree. The high school graduation rate (or equivalent) is 98.4%. Notably, 44.7% of adults hold a graduate or professional degree, indicating a highly educated workforce.
Data Sources & Methodology
All demographic data for Mercer Island, Washington is sourced from the U.S. Census Bureau's American Community Survey (ACS) 2020–2024 5-Year Estimates. The ACS collects data from approximately 3.5 million households annually and pools five years of responses so that even small communities can be measured, though the margin of error widens as the population falls. Comparisons are made against Washington state averages and national averages calculated from the same dataset. Rankings reflect the city's position among all 628 Census-designated places in Washington. Read more about how these figures are produced on our methodology page, or visit data.census.gov for official data.
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Frequently Asked Questions
What is the population of Mercer Island, Washington?
Mercer Island, Washington has a population of 25,307 according to the most recent U.S. Census ACS 5-Year Estimates.
What is the median household income in Mercer Island, WA?
The median household income in Mercer Island is $219,069, which is 171% higher than the national median of $80,734.
What is the poverty rate in Mercer Island, WA?
The poverty rate in Mercer Island is 3.8%. This means approximately 957 residents live below the federal poverty line.
What is the racial makeup of Mercer Island, Washington?
Mercer Island's population is 63.3% White, 0.9% Black, 2.4% Hispanic/Latino, and 24.4% Asian.
What is the median home value in Mercer Island, WA?
The median home value in Mercer Island is $2,000,000+. The home-value-to-income ratio is 9.1x.
How educated is Mercer Island, Washington?
81.5% of adults (25+) in Mercer Island hold a bachelor's degree or higher, and 44.7% hold a graduate or professional degree.