ZIP code · Mercer Island · Washington · United States
ZIP code 98040 — Mercer Island
ZIP code 98040 serves Mercer Island, Washington.
- Postal code
- 98040Single source Value from one source, not cross-checked.
- City
- Mercer Island
- County
- King
- State
- Washington
- Country
- United States
- Coordinates
- 47.5603, -122.2281 — precision precise (locality)
View on OpenStreetMap - Population
- 25,282 (ZCTA, ACS 5-year)
- Median household income
- $202,359
- Median age
- 45.8
- Time zone
- America/Los_Angeles (UTC−8 / UTC−7 DST)
About this page
US ZIP codes have five digits. They are postal routing areas, not administrative boundaries: a ZIP can span more than one city or county, and the city shown is the primary USPS name for that code.
GeoNames · U.S. Census Bureau (ACS). Data generated on 2026-08-21. Methodology · Report an error on this page