† Citizen voting-age population estimated for prior cycles; 2004 predates the ACS and is extrapolated. Source: ACS 5-year, table B05003.
——
D+60R+60
20042024
Boundary by 2024 margin · Precinct returns · VEST · MIT Election Lab
People and households
Who lives here
Exact values for this place, its state, and the United States.
Race · ethnicity · ancestry
Communities and origins
GroupMercer IslandWashingtonUnited States
German14.4%14.5%12.5%
English13.2%12.1%9.5%
Irish10.3%9.8%9.4%
Italian4.1%3.1%4.8%
Norwegian4.1%4.0%—
American3.0%3.8%5.3%
Swedish2.9%1.8%—
Scottish2.8%2.6%1.3%
Chinese6.8%2.2%1.3%
Asian Indian6.0%2.0%1.4%
Filipino2.7%1.5%0.9%
Vietnamese2.6%1.1%0.6%
Korean1.9%0.9%0.4%
Japanese1.1%0.4%0.2%
Taiwanese0.5%——
Cambodian0.4%0.3%—
Mexican1.5%10.8%11.3%
Hispanic or Latino counts residents of any race; the race groups count only their non-Hispanic residents, so the groups are mutually exclusive and sum to 100%. Expand a row to see ancestries reported within that group.
Age and life stage
Measure
Mercer Island
Washington
United States
Median age
46.4
38.5
39.1
Age 18–24
6.5%
8.5%
9.2%
Age 65 and older
22.1%
16.7%
17.2%
Household economy
Measure
Mercer Island
Washington
United States
Median household income
$219,069
$98,141
$84,427
Poverty rate
3.8%
9.9%
12.5%
Bachelor's degree or higher (25+)
81.4%
39.3%
35.6%
Languages at home
Measure
Mercer Island
Washington
United States
Speaks a non-English language at home
25.6%
21.5%
22.3%
Other Indo-European
6.0%
2.1%
2.0%
Korean
2.4%
0.8%
0.3%
Chinese (incl. Mandarin & Cantonese)
9.4%
1.9%
1.1%
Other Asian & Pacific Island
1.9%
2.1%
1.1%
Religious landscape
Measure
Mercer Island
Washington
United States
Catholic
—
10.7%
18.6%
Evangelical Protestant
—
20.5%
16.5%
Unclaimed / not counted
—
58.8%
51.5%
American Community Survey 2024 5-year (CVAP, income, age, poverty, education, language, race, ancestry) · presidential returns from MIT Election Lab through 2024 · 2020 U.S. Religion Census (ASARB) — congregational adherents; unclaimed is the residual not counted by congregations.
Mercer Island, Washington
presidential history
Presidential margin, 2004–2024
Democratic minus Republican, by election
Presidential margin over time
Year
Margin (D minus R)
2004
+22.4%
2008
+34.1%
2012
+26.8%
2016
+50.5%
2020
+54.5%
2024
+53.8%
DemocraticRepublican
6 presidential elections
Third column names the leading third-party or independent finisher. Source · MIT Election Lab · ICPSR · VEST (precinct-level 2024). Swing · margin change from the prior cycle. vs U.S. · margin relative to the national result that year. Third-party votes in 2012 are allocated from certified county totals by this place's share of each county's two-party vote — that cycle's precinct source records two-party splits. † 2004 sub-county results are estimated: the source's block-level detail for this cycle was unreliable — either county/municipality-level consolidated reporting (COVID-era) or a precinct-to-block allocation that misplaced votes — so the figures are allocated from the constituent county totals in proportion to the place and scaled to certified totals.
Year
Won
Democratic
Republican
Other
Margin
Swing
vs U.S.
Total
D
75.1%Harris11,716
21.3%Trump3,321
3.6%
D+53.8
R+0.6
D+55.3
15,598
D
76.0%Biden12,768
21.5%Trump3,617
2.5%
D+54.5
D+4.0
D+50.0
16,804
D
72.7%Clinton10,721
22.2%Trump3,272
5.1%
D+50.5
D+23.7
D+48.4
14,751
D
61.9%Obama9,682
35.2%Romney5,497
2.9%
D+26.8
R+7.3
D+22.9
15,634
D
66.5%Obama9,718
32.4%McCain4,735
1.1%
D+34.1
D+11.7
D+26.8
14,617
D
60.7%Kerry8,707
38.3%Bush5,491
1.1%
D+22.4
—
D+24.9
14,352
Mercer Island sits entirely on an island in Lake Washington, giving it unusually defined boundaries for a suburb. Its high household incomes and strong educational attainment correlate with some of the highest voter-participation rates in King County.
Across the recorded series it reached a Democratic high of 54.5 points in 2020. Between 2020 and 2024 the city moved 0.6 points toward the Republican candidate; the 2024 margin was 53.8 points.
A population of 25,307, a 65% non-Hispanic-white share, and a median household income of $219,069 describe the city. The city's voting pattern over the last decade is most similar to that of Union Hill-Novelty Hill and Woodinville.
Akashic
Political twins — cities
The cities whose fingerprint — 2000–2024 trajectory, demographics, ancestry, religion — sits closest to this one, and why.
Twin score (0–100) = weighted cosine between tier-standardized fingerprints: presidential margins 2000–2024 with 12-yr trend and elasticity, ACS income, age, education, population and race, top reported ancestries, and religious adherence — chips name the closest-shared dimensions and the widest gap. Re-weight the groups in the twins explorer.
In 2024, Mercer Island, Washington voted Democratic by 53.8 points (D+53.8), carried by the Democratic candidate. Out of 15,598 votes cast, 11,716 went Democratic and 3,321 went Republican.
How many people live in Mercer Island, Washington?
Mercer Island, Washington has a population of 25,307 according to the 2024 American Community Survey 5-year estimates from the US Census Bureau.
What is the median household income in Mercer Island, Washington?
Median household income in Mercer Island, Washington is $219,069 — above the national median of $80,734. The Washington state median is $98,141.
What is the political history of Mercer Island, Washington?
Akashic tracks 6 presidential elections in Mercer Island, Washington from 2004 to 2024. Of those, 6 went Democratic and 0 went Republican.
