Middlesex County, NJ Political Map | Democrat & Republican Areas in Middlesex County

By the BestNeighborhood data science team. Last updated May 2026.

Middlesex County leans slightly Democratic by roughly 12 points: about 56% of voters vote Democratic and 44% Republican.

 

About 62% of adults in Middlesex County typically vote, near the U.S. average of about 62%. Among adults in Middlesex County, ~35% vote Democratic, ~27% Republican, and ~38% don't vote. The map below shows estimated turnout by block group.

How Middlesex County compares

Among counties within 50 miles, Middlesex County leans more Democratic than 12 of 23 neighbors.

Middlesex County runs about 6 points more Democratic than New Jersey as a whole.

Politics vary noticeably by city within Middlesex County. The west side runs the most Democratic (D+35) and the southeast side runs the most Republican (R+10), a spread of about 44 points.

Why Middlesex County leans the way it does

This analysis examined 14,881 data points per county to find what predicts political lean and turnout. The items below are a few correlations that stood out for Middlesex County, not a ranked or complete list of what matters most.

Dense areas vote Democratic. About 86% of residents in Middlesex County live in densely developed areas, about 49 points above the U.S. average of 36%. High college attainment predicts Democratic voting, and Middlesex County sits in the top quarter (about 46%, above 95% of counties). A high never-married share predicts Democratic voting, and about 33% of adults in Middlesex County have never been married, above 78% of counties.

Walkability and Democratic lean

Places with a highly walkable street grid tend to lean Democratic; Middlesex County, NJ sits in the top tenth nationally on this measure. A walkable street grid does not change how people vote; it mostly reflects how urban a place is.

Why turnout in Middlesex County looks the way it does

Crowded housing lines up with lower turnout. About 6% of homes in Middlesex County have more than one occupant per room, above 95% of counties. Strong routine healthcare access lines up with higher turnout, and Middlesex County sits in the top quarter on routine-care measures. Renters vote less often than owners, and about 36% of households in Middlesex County rent, above 88% of counties. Learn more about the findings and methodology on the political spectrum map.

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Sources and methodology

Precinct-level voting records used to fit the model come from New Jersey Division of Elections, distributed by the Voting and Election Science Team. Demographic inputs come from the U.S. Census Bureau (ACS 5-year estimates and the 2020 Decennial Census). Health and environmental inputs come from the CDC (PLACES and the Environmental Justice Index). Land cover comes from the USGS and EPA. Election-day and lead-up weather come from PRISM 4km daily grids and the NOAA Global Historical Climatology Network. Mail-voting and election-administration patterns come from the MIT Election Lab's Survey of the Performance of American Elections. Block-group crime detail comes from CrimeGrade. Internet data and modeling support provided by ISPreports.org.

Modeling and analysis by the BestNeighborhood data science team. Full methodology and findings: political spectrum map.

Methodology reviewed by the BestNeighborhood data team. Last updated May 2026.