County record · fips 34021 · New Jersey
MercerNJ
Democratic ×10 since 1988all 40 elections, 1868–2024
The Long Record
40 elections against the New Jersey and national vote
2024 result
D+34.6
won by Democrats
Record since first cycle
22–18
Dem–Rep two-party wins
Voted with the winner
27/40
68% of its elections
Closest election
1876
R+0.4
this countyNew Jerseynational (official)dot colour = two-party winner · hollow = tie or unknown total · click a dot to open that election
The Biggest Swings
Cycle-over-cycle change in the two-party margin, in points
| Election | Swing | Toward |
|---|---|---|
| 1912 | +38.9 pts | Democrats |
| 1896 | -37.4 pts | Republicans |
| 1916 | -30.1 pts | Republicans |
| 1936 | +29.3 pts | Democrats |
| 1968 | -26.1 pts | Republicans |
Who Lives Here
Census & ACS county profile, 2024
Population
385,864
College (BA+)
45%
Median income
$100,645
2024 dollars
Non-white
57%
Rural
5%
Age 65+
16%
Interpolated between Census/ACS anchors; income CPI-deflated to 2024. Demographics begin in 2000 — earlier cycles have returns only.
Neighbouring counties
Burlington, NJ · Hunterdon, NJ · Middlesex, NJ · Monmouth, NJ · Somerset, NJ · Bucks, PA