Mercer Island, WA ZIP code
The ZIP code for Mercer Island, Washington is 98040. It is in King County.
- Population in these ZIPs
- 25,307
- Avg. median income
- $219,100population-weighted
- Typical home value
- $2,212,700population-weighted
- Metro area
- Seattle-Tacoma-Bellevue, WA
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Mercer Island, WA ZIP code list
| ZIP code | Population | Median income | Typical home value |
|---|---|---|---|
| 98040 | 25,307 | $219,069 | $2,212,700 |
Population and median household income: ACS 2020–2024 5-year estimates. Typical home value: Zillow Home Value Index (September 2026) where available, otherwise the ACS median owner-reported value. "PO Box" marks ZIP codes with no delivery area of their own. Methodology
Cities near Mercer Island
Frequently asked questions
What is the ZIP code for Mercer Island, WA?
The ZIP code for Mercer Island, WA is 98040.
What county is Mercer Island, Washington in?
Mercer Island ZIP codes are in King County.