Mercer County, New Jersey: New American county. In 2024, voted D+34%. Democratic peak: D+42 in 1964.
Key facts
- 2024 presidential margin
- D+34MIT Election Lab
- Political typology
- New AmericanAkashic typology
- Population
- 385,8642024 5-year
- Median household income
- $100,6452024 5-year
- White (non-Hispanic)
- 46.2%2024 5-year
- Black
- 18.5%2024 5-year
- Hispanic / Latino
- 23.1%2024 5-year
- Peak Democratic margin
- D+42 in 1964MIT Election Lab
- Peak Republican margin
- R+38 in 1896MIT Election Lab
- Most similar
- DeKalb County, GA · similarity 1.00
2024 results by precinct
2024 precinct map of Mercer CountyPrecinct-level 2024 presidential results for Mercer County, with each precinct boundary colored by Democratic-vs-Republican margin.
—
Margin—
Turnout—
Harris +50Trump +50
Real precinct boundaries. Hover for vote totals.
presidential history
Presidential margin, 1876–2024
Democratic minus Republican, by election
| Year | Margin (D minus R) |
|---|---|
| 1876 | No data |
| 1880 | No data |
| 1884 | No data |
| 1888 | No data |
| 1892 | −2.3% |
| 1896 | −38.0% |
| 1900 | −26.7% |
| 1904 | −26.0% |
| 1908 | −22.3% |
| 1912 | +9.9% |
| 1916 | −14.1% |
| 1920 | −29.8% |
| 1924 | −31.1% |
| 1928 | −19.0% |
| 1932 | −5.1% |
| 1936 | +23.7% |
| 1940 | +14.8% |
| 1944 | +17.4% |
| 1948 | +13.3% |
| 1952 | +6.7% |
| 1956 | −3.1% |
| 1960 | +22.5% |
| 1964 | +42.5% |
| 1968 | +14.2% |
| 1972 | −5.3% |
| 1976 | +8.5% |
| 1980 | +5.8% |
| 1984 | −3.5% |
| 1988 | +2.5% |
| 1992 | +14.4% |
| 1996 | +28.2% |
| 2000 | +27.0% |
| 2004 | +23.4% |
| 2008 | +36.1% |
| 2012 | +36.7% |
| 2016 | +37.1% |
| 2020 | +40.4% |
| 2024 | +33.8% |
DemocraticRepublican
38 presidential elections
| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| D | 107,558 | 52,274 | 163,779 | ||
| D | 122,532 | 51,641 | 175,600 | ||
| D | 104,775 | 46,193 | 158,058 | ||
| D | 104,377 | 47,355 | 155,355 | ||
| D | 107,926 | 50,223 | 160,039 | ||
| D | 91,580 | 56,604 | 149,510 | ||
| D | 83,256 | 46,670 | 135,559 | ||
| D | 77,641 | 40,559 | 131,726 | ||
| D | 71,383 | 50,473 | 145,260 | ||
| D | 68,712 | 65,384 | 135,345 | ||
| R | 66,398 | 71,195 | 138,121 | ||
| D | 60,888 | 53,450 | 128,582 | ||
| D | 69,621 | 58,453 | 130,856 | ||
| R | 62,180 | 69,303 | 133,191 | ||
| D | 63,218 | 45,354 | 125,529 | ||
| D | 86,985 | 35,081 | 122,214 | ||
| D | 74,166 | 46,924 | 121,269 | ||
| R | 52,684 | 56,029 | 109,105 | ||
| D | 57,751 | 50,423 | 108,662 | ||
| D | 49,690 | 37,794 | 89,436 | ||
| D | 52,383 | 36,844 | 89,371 | ||
| D | 50,121 | 37,190 | 87,533 | ||
| D | 47,702 | 29,283 | 77,564 | ||
| R | 30,284 | 33,715 | 66,879 | ||
| R | 27,908 | 41,056 | 69,338 | ||
| R | 14,639 | 30,689 | 51,551 | ||
| R | 15,713 | 29,626 | 46,683 | ||
| R | 10,621 | 14,213 | 25,493 | ||
| D | 7,773 | 5,676 | 21,120 | ||
| R | 9,289 | 14,941 | 25,329 | ||
| R | 8,527 | 14,900 | 24,467 | ||
| R | 7,858 | 13,874 | 22,498 | ||
| R | 5,970 | 13,847 | 20,718 | ||
| R | 9,348 | 9,795 | 19,671 | ||
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Demographics
2024 ACS
Race, ethnicity, and ancestry
Click any group to see the ancestries typically reported within it.
Italian
10.2%
Irish
9.8%
German
8.3%
English
5.7%
Polish
4.9%
American
2.4%
French
1.0%
African American
14.8%
Multiple ancestry combinations reported; no single grouping above 1%.
American Indian, Alaska Native, Native Hawaiian, and Pacific Islander combined.
Source · American Community Survey 5-year estimates, 2024 release. Hispanic/Latino is an ethnicity that overlaps the race categories, so these shares can total more than 100%. Ancestry is a self-reported, multiple-response item; ancestry percentages do not sum to the parent race percentage.
2024 ACS
Age distribution by sex
Median age: 39.5 in this county, 39.1 nationally
Male
Age
Female
85+
75–84
65–74
55–64
45–54
35–44
25–34
18–24
5–17
<5
Source · American Community Survey 5-year estimates, 2024 release.
2024 ACS
Median household income
Inflation-adjusted dollars
$100,645
Mercer County ranks in the top 5% of US counties.
Mercer County$100,645
New Jersey$103,556
United States$80,734
Mercer County ranks in the top 5% of US counties by median household income.
Source · American Community Survey 5-year estimates, 2024 release.
2024 ACS
Poverty rate
All persons below federal poverty line
10.3%
Child poverty is below the national average.
Children under 1813.2%
Working age (18–64)9.3%
Seniors (65+)10.3%
Source · American Community Survey 5-year estimates, 2024 release.
2024 ACS
Language at home
Population aged 5 and older
64.3%
speak English only
Spanish19.1%
Other Indo-European9.2%
Asian & Pacific Islander5.8%
Other languages1.7%
Source · ACS 5-year estimates, 2024.
2020 religion census
Religious adherents
Adherents per capita by tradition
Source · 2020 US Religion Census. Remaining 52.1% of residents not counted as adherents by any reporting body.
Mercer County anchors New Jersey's political center of gravity around Trenton, returning Democratic presidential margins above 30 points in recent cycles while housing a mix of urban wards, suburban townships, and Princeton's academic community.
Mercer County has leaned Democratic in recent presidential elections, reaching a Democratic margin of forty-two points in 1964. Between 2020 and 2024 it moved seven points toward the Republican candidate — part of the sharpest rightward shift recorded among any group of places in the country.
Its demographics describe the shift: a 46% non-Hispanic-white share, a median household income of $100,645, and a population of 385,864. The county's voting pattern over the last decade is most similar to that of DeKalb County and Norfolk city.
Most similar counties
Compare two places, side by side
Twelve curated comparisons line up election history, demographics, and the divergence story for two places at a glance. Browse all comparisons →
Cite this page
All citations released under CC BY 4.0. Attribution: Akashic Intelligence.
Mercer County, New Jersey. Akashic. https://akashic.app/county/34021/. Accessed May 20, 2026. License: CC BY 4.0.
License: CC BY 4.0
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Frequently asked questions
How did Mercer County, New Jersey vote in 2024?
In 2024, Mercer County, New Jersey voted Democratic by 33.8 points (D+34), carried by the Democratic candidate. Out of 163,779 votes cast, 107,558 went Democratic and 52,274 went Republican.
What is Mercer County, New Jersey's political typology?
Akashic places Mercer County, New Jersey in the "New American" typology — Communities where a large share of households speak a language other than English — multilingual, Democratic-leaning overall, yet the hardest-swinging bloc toward the Republican Party in 2024. The typology is a data-driven cluster built from vote share, vote swing, race and ethnicity, income, language spoken at home, religion, and ancestry. Across 38 elections in the dataset, the county has voted Democratic 21 times, Republican 13 times, and other 0 times.
When did Mercer County, New Jersey last vote Republican?
The most recent presidential election in which Mercer County, New Jersey voted Republican was 1984.
How many people live in Mercer County, New Jersey?
Mercer County, New Jersey has a population of 385,864 according to the 2024 American Community Survey 5-year estimates from the US Census Bureau.
What is the median household income in Mercer County, New Jersey?
Median household income in Mercer County, New Jersey is $100,645 — above the national median of $80,734. The New Jersey state median is $103,556.
What is the political history of Mercer County, New Jersey?
Akashic tracks 38 presidential elections in Mercer County, New Jersey from 1876 to 2024. Of those, 21 went Democratic and 13 went Republican. The county's typology — "New American" — captures where that record, its demographics, and its recent swing place it among American communities.