Residential delivery area · Washington
ZIP Code 98040: Mercer Island, WA
ZIP code 98040 is in Mercer Island, Washington, entirely in King County (Census 2020 ZIP-county file). About 25,000 people live there (Census Bureau, ACS 2020-2024). Median household income is $219,069 (Census Bureau, ACS 2020-2024).
- ACS2020-24
- Census2020
- FHFA2023
- ZBP2023
- IRS2022
- Town
- Mercer Island · its only residential ZIP
- County
- King County
- Census places
- Mercer Island
- Metro area
- Seattle-Tacoma-Bellevue, WA
- House district
- WA-9 119th Congress
- State
- Washington
- Time zone
- Pacific
- Land area
- 6.4 sq mi · 3,965 people per sq mi
Where is ZIP code 98040?
98040 centers on 47.564°, -122.231° and covers 6.4 square miles of land plus 6.5 of water. It borders 8 ZIP codes: 98118, 98144, 98006, 98004, 98056, 98122, 98178, 98039.
The map draws ZIP code areas only. For the streets inside 98040, open its center on OpenStreetMap.
Source: U.S. Census Bureau, 2020 ZCTA cartographic boundaries and the 2023 Gazetteer (2020 ZCTAs); ZIP-to-county shares, Census places and House districts (119th Congress) from the Census 2020 relationship files (shares of land); metro area from the OMB delineation (July 2023); town name and time zone from simplemaps US ZIP Codes (CC BY 4.0).
How does 98040 compare with the rest of King County?
| Measure | 98040 | In King County | In WA |
|---|---|---|---|
| People (ACS 2020-2024) | 25,307 | 48th of 89 | 137th of 605 |
| Median household income | $219k | 4th of 78 | 4th of 363 |
| Median home value | $2M+ | 1= of 78 | 1= of 392 |
1= means a shared first place: 98040's median home value ties with 2 other ZIP codes at the Census cap in King County; median home value ties with 2 other ZIP codes at the Census cap in Washington.
Its median household income is higher than in 99% of U.S. residential ZIP codes, and it is denser than 92% of all U.S. residential ZIP codes. ZIP codes at the ACS caps ($250,000 or more for household income, $2,000,000 or more for home value) share the top rank.
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B01003, B19013, B25077); ranks by PlainZIP over residential ZIP codes (ZCTAs).
How many people live in 98040?
The 2020 Census counted 25,748 people in 98040; the ACS, which samples households over 2020-2024, estimates 25,307. Between the 2010 and 2020 censuses its population grew 13.4% (its boundary stayed at least 90% the same).
- People, ACS 2020-2024
- 25,307
- 2020 Census count
- 25,748+13.4% since 2010 (22,699)
- Households
- 10,068
- Median age
- 46.4
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B01003, B01002, B11001); 2020 Census (DHC P1); 2010 Census (SF1 P1).
Who lives in 98040?
Of the 25,307 people the ACS estimates in 98040, 21.5% are under 18 and 22.2% are 65 or older. The largest group by race and Hispanic origin is White (not Hispanic) (63.3%), then Asian (not Hispanic) (24.4%).
- Under 1821.5%
- 18 to 6456.4%
- 65 and older22.2%
- White, not Hispanic63.3%
- Asian, not Hispanic24.4%
- Other or two or more9.0%
- Hispanic or Latino2.4%
- Black, not Hispanic0.9%
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B01001 age by sex, B03002 Hispanic or Latino origin by race); shares of the estimated population, small ZIP codes carry wide margins.
What do households in 98040 earn?
Median household income is $219,069 (ACS 2020-2024), the 4th highest of the 78 ranked ZIP codes in King County. It rose from $181,062 in 2015-2019 (in 2024 dollars), a change larger than the surveys' margins of error.
- Median household income
- $219,069
- Income per person
- $128,615
- Below the poverty line
- 3.8%
- Unemployed (of the labor force)
- 3.0%
- Adults 25+ with a bachelor's degree
- 81.4%
- Adjusted gross income per tax return, 2022
- $408,31212,700 returns; wages 49% of AGI (IRS)
Source: U.S. Census Bureau, ACS 2020-2024 and 2015-2019 5-year estimates (B19013, B19301, B17001, B23025, B15003; 2015-2019 dollars converted with the BLS CPI-U, 1.22699); IRS Statistics of Income, ZIP code data, tax year 2022 (adjusted gross income per return, filed under the address on the return).
What are homes worth in 98040?
- Median home value (owners' estimate)
- $2,000,000 or more
- Median gross rent
- $2,502
- Homes owned by their occupants
- 67.0%
- Housing units
- 10,609
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B25077, B25064, B25003, B25001); FHFA House Price Index, annual five-digit ZIP, updated 2026-03-31.
What businesses are in 98040?
830 business establishments had a location in this ZIP code in 2023, 2 fewer than in 2018; the most are in professional, scientific, and technical services (ZIP Code Business Patterns).
- Professional, scientific, and technical services182
- Real estate and rental and leasing115
- Health care and social assistance108
- Finance and insurance81
- Other services (except public administration)63
- Construction53
Source: U.S. Census Bureau, ZIP Code Business Patterns 2023 and 2018 (establishments with paid employees, by the business's ZIP code).
Which ZIP codes are next to 98040?
| ZIP | Town | People | Household income | Distance |
|---|---|---|---|---|
| 98118 | Seattle | 50,500 | $114k | 2.3 mi |
| 98144 | Seattle | 33,787 | $97k | 3.2 mi |
| 98006 | Bellevue | 40,009 | $198k | 3.8 mi |
| 98004 | Bellevue | 39,897 | $183k | 3.9 mi |
| 98056 | Renton | 35,849 | $114k | 4.1 mi |
| 98122 | Seattle | 43,234 | $107k | 4.3 mi |
| 98178 | Seattle | 26,748 | $100k | 4.6 mi |
| 98039 | Medina | 2,928 | $250k+ | 4.9 mi |
| 98108 | Seattle | 25,529 | $96k | 4.0 mi (near) |
| 98005 | Bellevue | 21,846 | $161k | 4.5 mi (near) |
Source: PlainZIP from the Census 2020 ZCTA boundaries (shared edges) and internal points; figures ACS 2020-2024.