2024
D+24.2marginKamala HarrisDem
147,327
61.2%
Donald TrumpRep
89,063
37.0%
All other candidates
4,242
1.8%
240,632 ballots cast · 40.2 per 100 residents (2024 population estimate)
Residents598,743+4.4% since 2020 (+25,261 people)
Union County
New Jersey·FIPS 34039·601,863 residents (2025 estimate)
2024 result
D+24.2
240,632 ballots cast
What happened: the county's margin each cycle, against the national result.
Lean vs. nation
D+26.2
How this county sits relative to the country in 2024, with the national environment removed.
Trend since 2000
+2.7 pts
Net movement of that lean across 7 cycles — toward Democrats.
Elasticity
1.32
Moves roughly in step with the country.
Bellwether error
26.8
Average gap between this county's margin and the nation's.
3 consecutive cycles moving toward Democrats relative to the nation.
Votes by candidate
7 cyclesCertified vote counts for each party's nominee, the combined total for everyone else on the ballot, the number of ballots cast, and how many people lived here at the time.
2020
D+35.7marginJoe BidenDem
170,245
67.3%
Donald TrumpRep
80,002
31.6%
All other candidates
2,744
1.1%
252,991 ballots cast · 44.1 per 100 residents (2020 population estimate)
Residents573,482+3.7% since 2016 (+20,701 people)
Measured across a change of Census vintage. The two series share no common year, so how far apart they sit cannot be measured — this change carries an unknown amount of revision on top of four years of real change.
2016
D+35.7marginHillary ClintonDem
147,414
66.4%
Donald TrumpRep
68,114
30.7%
All other candidates
6,447
2.9%
221,975 ballots cast · 40.2 per 100 residents (2016 population estimate)
Residents552,781+1.8% since 2012 (+9,811 people)
2012
D+34.0marginBarack ObamaDem
139,752
66.6%
Mitt RomneyRep
68,314
32.6%
All other candidates
1,765
0.8%
209,831 ballots cast · 38.6 per 100 residents (2012 population estimate)
Residents542,970+2.9% since 2008 (+15,442 people)
Measured across a change of Census vintage. Where the two vintages overlap, 96% of counties agree within 0.5%, so read this figure to about half a point and no finer.
2008
D+28.4marginBarack ObamaDem
141,417
64.1%
John McCainRep
78,768
35.7%
All other candidates
465
0.2%
220,650 ballots cast · 41.8 per 100 residents (2008 population estimate)
Residents527,528+0.1% since 2004 (+612 people)
2004
D+18.1marginJohn KerryDem
119,372
58.7%
George W. BushRep
82,517
40.6%
All other candidates
1,498
0.7%
203,387 ballots cast · 38.6 per 100 residents (2004 population estimate)
Residents526,916+0.7% since 2000 (+3,792 people)
2000
D+23.3marginAl GoreDem
112,003
60.1%
George W. BushRep
68,554
36.8%
All other candidates
5,816
3.1%
186,373 ballots cast · 35.6 per 100 residents (2000 population estimate)
Residents523,124
“All other candidates” is every remaining line on the presidential ballot combined — minor parties, independents and write-ins where the state reports them. Shares are of all ballots cast, so the three rows sum to 100%.
Ballots cast per 100 residents is not a turnout rate. It measures votes against every resident — children and non-citizens included — not against eligible or registered voters, which is what turnout means and which this site does not have a county-level figure for. It is shown only where an election year and a population estimate share the same year and describe the same territory; where the Census figure is stated on boundaries the vote was not cast on, the card says so and the ratio is withheld.
A change in residents is not a change in voters. The percentage beside each year is the change in resident population since the previous presidential election — everyone who lives here, including children and non-citizens. It is not turnout, not registration, and not the same quantity as the change in ballots cast. Population is measured on 1 July of the election year, four months before the vote, which is the closest an annual series gets to election day.
Population figures on this page come from 3 Census series: PEP intercensal county estimates, 2000–2010; PEP vintage 2019 county estimates, 2010–2019; PEP vintage 2025 county estimates, 2020–2025. The 2012 and 2020 figures are the first in a new series, so the change shown for those years is measured across a change of Census method as well as across four years. Each of those cards says so. Two figures drawn from different vintages are not two readings of one series.
Every cycle
| Year | Margin | Lean | Swing | Rel. swing | Votes | 3rd party |
|---|---|---|---|---|---|---|
| 2024 | D+24.2 | D+26.2 | -11.4 | -5.4 | 240,632 | 1.8% |
| 2020 | D+35.7 | D+31.6 | -0.7 | -3.0 | 252,991 | 1.1% |
| 2016 | D+35.7 | D+34.6 | +2.5 | +4.3 | 221,975 | 2.9% |
| 2012 | D+34.0 | D+30.3 | +5.9 | +9.3 | 209,831 | 0.8% |
| 2008 | D+28.4 | D+21.1 | +10.2 | +0.3 | 220,650 | 0.2% |
| 2004 | D+18.1 | D+20.7 | -5.8 | -2.7 | 203,387 | 0.7% |
| 2000 | D+23.3 | D+23.4 | — | — | 186,373 | 3.1% |
Margin is over all votes cast. Lean is the two-party margin minus the nation's — the county's own position with the national environment removed. Relative swing is the change in that lean. “Votes” is the number of ballots cast in the presidential contest, not a share of eligible voters.
Counties on a similar trajectory
Sources
Presidential returns from the MIT Election Data and Science Lab (County Presidential Returns 2000–2024, CC0). Geography and FIPS codes from the US Census Bureau (public domain). Where a state reports both a total and per-mode vote counts, the reported total is used.
Resident population from the US Census Bureau, Population Estimates Program (Vintage 2025), measured as of July 1, 2025. Resident population — all residents, including children and non-citizens. Not an electorate, and not comparable to a vote total as a turnout rate. Conclusions drawn from it are ours, not the Bureau's.
Population at each election is measured on 1 July of the election year and comes from the US Census Bureau's Population Estimates Program (public domain). The 2000–2024 span is covered by several separately estimated vintages of that programme rather than by one continuous series — the ones used on this page are named under the cycle cards, and every change measured across a boundary between them is marked there. Notes about territory changing hands come from this site's own change ledger and are only as complete as it is.