Mercer Island ZIP Codes — King County, WA

There is one unique ZIP code in Mercer Island, Washington and it is 98040. Area code: 206.
1
ZIP codes
6.38
sq mi land
6.52
sq mi water
206
area code
Mercer Island, WA ZIP code map

About Mercer Island, WA

Mercer Island, WA is a picturesque city located in the heart of King County. Known for its scenic beauty and suburban charm, it provides a quiet refuge while being just a short drive from the bustling Seattle metropolitan area. The community is characterized by its stunning waterfront views and vibrant neighborhoods, making it a desirable place to live and work.

Location & geography

Mercer Island is situated on Lake Washington, and it offers lush landscapes and water views that are both captivating and serene. The island is approximately 6.38 square miles in land area and is surrounded by a water area of 6.52 square miles, showcasing the beauty of its aquatic environment. Nearby cities include Bellevue, just 4 miles to the east, Seward Park at 5 miles to the northwest, Renton approximately 8 miles to the south, and Seattle located about 10 miles to the northwest.

Community & economy

Mercer Island is a well-established community with a mix of families, professionals, and retirees, contributing to its vibrant character. The local economy thrives on industries such as technology, retail, and education, offering various employment opportunities for its residents. Daily life includes a strong focus on outdoor recreation, with numerous parks, community events, and access to the beautiful waterfront.

Transportation

Mercer Island is conveniently accessed via Interstate 90, which connects it to Seattle and Bellevue, facilitating easy travel for commuters. The nearest major airport is Seattle-Tacoma International Airport, located about 15 miles to the south of the island. Public transit options include King County Metro bus services that operate throughout the island and link to surrounding areas.

History

Mercer Island was originally settled by Native American tribes long before European Americans arrived in the late 1800s. The area rapidly developed in the early 20th century, becoming popular for its natural beauty and evolving industries, including farming and tourism. Notably, the construction of the I-90 floating bridge in 1940 significantly increased accessibility to the island, shaping its growth and development.

Did you know?

One surprising fact about Mercer Island is that it is home to the world's largest floating bridge, the I-90 floating bridge, which connects the island to Seattle. Additionally, the island was a notable site during World War II, when it served as an internment location for Japanese Americans.

ZIP codes for Mercer Island, WA (1)
ZIP code City County Map
98040 Mercer Island King View map

Demographics & statistics

25,464
Population
45.3
Median age
$190,985
Median household income
$113,575
Per capita income
$1,683,600
Median home value
$2,315
Median monthly rent
68.0%
Home ownership
5.3%
Poverty rate
2.6%
Unemployment
7,381
Housing units
77.7%
Bachelor's or higher

Age distribution

Male Female
486
Under 5
544
784
5–9
879
911
10–14
1,022
899
15–19
1,007
379
20–24
424
999
25–34
1,119
1,470
35–44
1,647
2,035
45–54
2,281
864
55–59
968
727
60–64
814
1,227
65–74
1,375
731
75–84
819
496
85+
557
← Male
Female →

Age summary

GroupCount%
Under 185,88223.1%
18 and over19,58276.9%
65 and over5,20520.4%
Median age45.3 years

Race & ethnicity

White 64.3%
Asian 21.6%
Two or more races 8.6%
Hispanic or Latino 3%
Black or African American 1.3%
Other race 1.1%
American Indian / Alaska Native 0.1%
GroupCount%
White16,88264.3%
Asian5,65821.6%
Two or more races2,2648.6%
Hispanic or Latino7783%
Black or African American3401.3%
Other race2961.1%
American Indian / Alaska Native240.1%

Household income

Under $10k 2.9%
$10k–$15k 0.6%
$15k–$25k 2.9%
$25k–$35k 5.2%
$35k–$50k 4.5%
$50k–$75k 9.0%
$75k–$100k 5.6%
$100k–$150k 12.3%
$150k–$200k 8.7%
$200k+ 48.3%
Range% of households
Under $10k2.9%
$10k–$15k0.6%
$15k–$25k2.9%
$25k–$35k5.2%
$35k–$50k4.5%
$50k–$75k9.0%
$75k–$100k5.6%
$100k–$150k12.3%
$150k–$200k8.7%
$200k+48.3%
Median income$190,985

Housing

Home values

Under $50k 0.7%
$100k–$150k 1.1%
$150k–$200k 0.1%
$200k–$300k 0.8%
$300k–$500k 4.5%
$500k–$1M 7.9%
$1M+ 84.9%

Housing overview

MetricValue
Median home value$1,683,600
Median rent / month$2,315
Owner occupied68.0%
Renter occupied32.0%
Vacant7.0%
Single-family detached65.8%
Large apartment buildings23.5%
Mobile homes0.5%
Median rooms6.8
Avg household size (owned)2.88

Year built

Era%
2020 or later0.5%
2010–20198.5%
2000–200911.7%
1990–19997.9%
1980–19899.9%
1970–197917.8%
1960–196922.0%
1950–195911.7%
1940–19496.6%
1939 or earlier3.2%

Bedrooms

Size% of units
No bedroom (studio)4.8%
1 bedroom11.9%
2 bedrooms19.2%
3 bedrooms19.1%
4 bedrooms29.0%
5+ bedrooms16.0%

Vehicles per household

Vehicles% of households
No vehicle6.1%
1 vehicle28.5%
2 vehicles41.2%
3 or more24.2%

Heating fuel

Fuel type%
Utility gas60.0%
Electricity36.3%
Propane / LP gas1.2%
Fuel oil1.2%
Wood0.2%
Solar0.1%
No fuel used0.7%

Households & families

Household typeCount%
Married-couple family6,29864.4%
Cohabiting couple3894.0%
Male householder, no spouse9659.9%
Female householder, no spouse2,13021.8%
Households with children under 183,33934.1%
Households with seniors (65+)3,41334.9%
Average household size2.59

Marital status

StatusMaleFemale
Never married23.5%21.0%
Married68.7%60.7%
Separated0.4%0.5%
Widowed2.4%8.9%
Divorced5.0%8.9%

Education

Less than 9th grade 1.5%
Some HS, no diploma 0.7%
HS graduate 5.7%
Some college, no degree 8.8%
Associate's degree 5.5%
Bachelor's degree 38.2%
Graduate / professional 39.6%
Metric%
HS diploma or higher97.8%
Bachelor's or higher77.7%

School enrollment (ages 3–17)

TypeCount%
Nursery / preschool5327.7%
Kindergarten2063.0%
Elementary school2,91442.3%
High school2,02229.4%
College / grad school1,20717.5%

Employment

Industry of employment

Professional & management 26.8%
Education & healthcare 20.8%
Finance & real estate 10.7%
Retail trade 10.1%
Arts, food & hospitality 6.3%
Information 5.6%
Manufacturing 5.2%
Other services 3.8%
Transportation & utilities 3.1%
Wholesale trade 3.0%
Construction 2.3%
Public administration 2.2%

Occupation

Category%
Management, business & arts70.6%
Service6.9%
Sales & office19.2%
Natural resources & construction1.2%
Production & transportation2.1%

Employment type

Type%
Private sector80.5%
Government9.7%
Self-employed9.5%
Unpaid family workers0.2%

Commute

Method%
Drive alone52.3%
Carpool6.4%
Public transit7.2%
Walk2.0%
Other means1.7%
Avg commute (minutes)27.0

Poverty

All people 5.3%
Under 18 years 6.0%
18 and over 5.0%
Married-couple families 2.5%
Female-led households 10.7%

Income support

Source% of households
Social Security27.8%
Retirement income24.5%
Supplemental Security2.2%
Cash public assistance1.7%
Food stamps / SNAP1.8%

Health indicators

Condition%
High blood pressure29.9%
High cholesterol34.0%
Heart disease5.3%
Stroke2.4%
Asthma8.3%
Arthritis22.5%
Kidney disease2.6%
Pulmonary disease3.6%
Cancer8.5%
Behavior / access%
Binge drinking15.5%
No physical activity11.3%
Less than 7 hrs sleep23.3%
Fair or poor health7.9%
Poor mental health9.9%
Poor physical health6.9%
No health insurance5.7%
Visited doctor (checkup)72.9%
Visited dentist79.9%
Cholesterol screening93.7%
Teeth loss4.6%

Veterans & disability

VeteransCount%
Civilian veterans8564.4%
Disability%
Any disability9.8%
Under 185.1%
18–64 years4.7%
65 and over29.8%

Health insurance coverage

Type%
Private insurance87.8%
Public insurance23.8%
Uninsured under 193.2%

Language & origin

Language spoken at home (age 5+)

LanguageCount%
English only24,43496.0%
Spanish1,8297.5%
Other Indo-European1000.4%
Asian & Pacific Islander3091.3%
Other languages1,4055.8%

Place of birth & citizenship

OriginCount%
Native born (US)19,20775.4%
Born in same state18,62473.1%
Born in different state8,72234.3%
Foreign born5832.3%
Naturalized citizen6,25724.6%
Not a US citizen3,70059.1%

Ancestry

AncestryCount%
French3,32213%
Italian2,2488.8%
Polish1,0124%
Arab6222.4%
German2931.2%
AncestryCount%
Dutch2380.9%
English2260.9%
Irish1710.7%
Norwegian1490.6%

Technology access

Metric% of households
Computer access38.4%
Internet access97.3%

Source: U.S. Census Bureau, American Community Survey 2025 estimates.

Frequently asked questions
What ZIP codes does Mercer Island, WA have?
Mercer Island, WA has one ZIP code: 98040. Each ZIP code serves a distinct delivery area within the city and surrounding region.
Need the complete Washington ZIP code database? Download all WA ZIP codes — Excel, CSV, or Access. Includes lat/lng, county FIPS & timezone.
Download database →