San Jose, CA Political Map | Democrat & Republican Areas in San Jose

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

San Jose leans heavily Democratic by roughly 32 points: about 66% of voters vote Democratic and 34% Republican.

 

About 56% of adults in the San Jose area typically vote, below the U.S. average of about 62%. Among adults in the San Jose area, ~37% vote Democratic, ~19% Republican, and ~44% don't vote. The map below shows estimated turnout by block group.

How San Jose compares

Among cities within 25 miles, San Jose leans more Democratic than 12 of 50 neighbors.

San Jose runs about 11 points more Democratic than California as a whole.

Politics vary noticeably by neighborhood within San Jose. The northwest side is the most Democratic-leaning (D+43) and the southeast side is the least Democratic-leaning (D+18), a spread of about 25 points.

Why San Jose 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 San Jose, not a ranked or complete list of what matters most.

Dense areas vote Democratic. About 95% of residents in the San Jose area live in densely developed areas, about 58 points above the U.S. average of 36%. High college attainment predicts Democratic voting, and San Jose sits in the top quarter (about 55%, above 95% of cities). A high never-married share predicts Democratic voting, and about 35% of adults in the San Jose area have never been married, above 88% of cities.

Population density and Democratic lean

Places with high population density tend to lean Democratic; San Jose, CA sits in the top tenth nationally on this measure.

Why turnout in San Jose looks the way it does

Renters vote less often than owners. About 42% of households in the San Jose area rent, about 17 points above the U.S. average of 25%. Crowded housing lines up with lower turnout, and about 8% of homes in the San Jose area have more than one occupant per room, above 95% 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.