Mercer Island city, Washington
Official LSAD Designation: Mercer Island city • Census GEOID: 5345005
• King County
Mercer Island city is an incorporated city in King County, Washington. According to official records from the Census (2025), Mercer Island city had an estimated population of 25,422 residents. Official Census Bureau geographic records classify this community under LSAD designation Mercer Island city (GEOID 5345005).
Local Government Administration U.S. Census Bureau GMAF
City Of Mercer Island
Municipal
Official Title:
City Clerk
Address:
9611 SE 36TH ST, MERCER ISLAND WA 98040-3732
County Of King
County
Official Title:
Demographer
Address:
401 5TH AVE, STE 800, SEATTLE WA 98104-2391
Civic & Statistical Snapshot
| Category | Estimate | Survey Period / Source |
|---|---|---|
| Total Population | 25,422 | 2025 |
| Median Household Income | $219,069 | 2020-2024 |
| Median Home Value | $2,000,000+ | 2020-2024 |
| Land Area | 6.38 sq mi | Gazetteer (2026) |
| Civic & Public Services | Hospitals, Libraries, Colleges | CMS / IMLS / IPEDS |
| Schools & Districts | NCES Directory Listings | Provided by k12guides.com |
| Nearby Airports | Landing Facilities | Provided by airport-data.com |
| Climate & Weather | NOAA 30-Year Normals | 1991–2020 |
Source: U.S. Census Bureau (PEP, ACS 5-Year).