† 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
GroupMountainsideNew JerseyUnited States
Italian18.8%13.7%4.8%
Irish14.8%12.1%9.4%
German10.2%8.6%12.5%
American8.4%3.3%5.3%
Polish8.2%4.6%2.2%
Portuguese5.6%0.4%—
English5.2%4.9%9.5%
Russian2.5%1.3%—
Puerto Rican1.8%5.1%1.8%
Colombian1.7%1.7%0.4%
Dominican1.7%4.0%0.7%
Salvadoran1.4%0.8%0.7%
Ecuadorian1.4%1.7%—
Cuban0.8%0.9%0.7%
Guatemalan0.8%—0.5%
Mexican0.7%2.6%11.3%
Asian Indian3.8%4.6%1.4%
Chinese2.9%1.6%1.3%
Filipino2.9%1.3%0.9%
Korean0.4%1.1%0.4%
Pakistani0.4%0.4%—
African American†1.4%8.6%9.9%
Haitian0.3%0.7%0.3%
Maya0.3%——
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
Mountainside
New Jersey
United States
Median age
48
40.3
39.1
Age 18–24
5.9%
8.4%
9.2%
Age 65 and older
24.2%
17.1%
17.2%
Household economy
Measure
Mountainside
New Jersey
United States
Median household income
$211,538
$103,556
$84,427
Poverty rate
3.7%
9.7%
12.5%
Bachelor's degree or higher (25+)
67.3%
43.5%
35.6%
Languages at home
Measure
Mountainside
New Jersey
United States
Speaks a non-English language at home
24.9%
33.2%
22.3%
Spanish
7.8%
17.2%
13.6%
Russian, Polish, or other Slavic
2.9%
1.7%
0.7%
Other Indo-European
4.5%
5.6%
2.0%
Chinese (incl. Mandarin & Cantonese)
7.6%
1.5%
1.1%
Religious landscape
Measure
Mountainside
New Jersey
United States
Catholic
—
32.0%
18.6%
Evangelical Protestant
—
5.1%
16.5%
Unclaimed / not counted
—
47.8%
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.
Mountainside, New Jersey
presidential history
Presidential margin, 2004–2024
Democratic minus Republican, by election
Presidential margin over time
Year
Margin (D minus R)
2004
−31.8%
2008
−21.5%
2012
−22.5%
2016
−11.5%
2020
+0.2%
2024
−4.2%
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
R
46.8%Harris2,101
51.1%Trump2,291
2.1%
R+4.2
R+4.4
R+2.8
4,485
D
49.7%Biden2,273
49.6%Trump2,266
0.7%
D+0.2
D+11.6
R+4.3
4,572
R
42.7%Clinton1,664
54.2%Trump2,110
3.1%
R+11.5
D+11.0
R+13.5
3,893
R
38.3%Obama1,333
60.7%Romney2,115
1.0%
R+22.5
R+1.0
R+26.3
3,482
R
38.8%Obama1,499
60.2%McCain2,329
1.0%
R+21.5
D+10.3
R+28.7
3,868
R
34.1%Kerry1,264
65.8%Bush2,443
0.1%
R+31.8
—
R+29.3
3,710
Mountainside is one of New Jersey's least-populous boroughs, with a median household income well above state norms. Its small electorate and high homeownership rate produce turnout figures that consistently outpace comparably sized communities.
Across the recorded series it reached a Democratic high of 0.2 points in 2020 and a Republican high of 31.8 points in 2004. Between 2020 and 2024 the city moved 4.4 points toward the Republican candidate; the 2024 margin was 4.2 points.
A population of 7,049, a 73% non-Hispanic-white share, and a median household income of $211,538 describe the city. The city's voting pattern over the last decade is most similar to that of North Caldwell and Roseland.
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, Mountainside, New Jersey voted Republican by 4.2 points (R+4.2), carried by the Republican candidate. Out of 4,485 votes cast, 2,101 went Democratic and 2,291 went Republican.
When did Mountainside, New Jersey last vote Democratic?
The most recent presidential election in which Mountainside, New Jersey voted Democratic was 2020.
How many people live in Mountainside, New Jersey?
Mountainside, New Jersey has a population of 7,049 according to the 2024 American Community Survey 5-year estimates from the US Census Bureau.
What is the median household income in Mountainside, New Jersey?
Median household income in Mountainside, New Jersey is $211,538 — above the national median of $80,734. The New Jersey state median is $103,556.
What is the political history of Mountainside, New Jersey?
Akashic tracks 6 presidential elections in Mountainside, New Jersey from 2004 to 2024. Of those, 1 went Democratic and 5 went Republican.
