Union City, CA Political Map | Democrat & Republican Areas in Union City

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

Union City leans heavily Democratic by roughly 34 points: about 67% of voters vote Democratic and 33% Republican.

 

About 50% of adults in Union City typically vote, below the U.S. average of about 62%. Among adults in Union City, ~34% vote Democratic, ~16% Republican, and ~50% don't vote. The map below shows estimated turnout by block group.

How Union City compares

Among cities within 25 miles, Union City leans more Democratic than 17 of 79 neighbors.

Union City runs about 13 points more Democratic than California as a whole.

Politics vary noticeably by neighborhood within Union City. The southeast side is the most Democratic-leaning (D+37) and the west side is the least Democratic-leaning (D+27), a spread of about 10 points.

Why Union City leans the way it does

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

Dense areas vote Democratic. About 91% of residents in Union City live in densely developed areas, about 54 points above the U.S. average of 36%. High college attainment predicts Democratic voting, and Union City sits in the top quarter (about 46%, above 91% of cities). A high never-married share predicts Democratic voting, and about 30% of adults in Union City have never been married, above 75% of cities.

Walkability and Democratic lean

Places with a highly walkable street grid tend to lean Democratic; Union City, CA 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 Union City looks the way it does

Renters vote less often than owners. About 33% of households in Union City rent, about 8 points above the U.S. average of 25%. Crowded housing lines up with lower turnout, and about 6% of homes in Union City have more than one occupant per room, above 92% of cities. 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 California Secretary of State, 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.