91302 leans slightly Democratic by roughly 12 points: about 56% of voters vote Democratic and 44% Republican.
About 74% of adults in 91302 typically vote, above the U.S. average of about 62%. Among adults in 91302, ~42% vote Democratic, ~33% Republican, and ~25% don't vote. The map below shows estimated turnout by block group.
How 91302 compares
Among zip codes within 15 miles, 91302 leans more Democratic than 8 of 49 neighbors.
91302 runs about 7 points more Republican than California as a whole.
Politics vary noticeably by block within 91302. The west side is the most Democratic-leaning (D+31) and the north side is the least Democratic-leaning (D+3), a spread of about 28 points.
Why 91302 leans the way it does
This analysis examined 14,881 data points per zip code to find what predicts political lean and turnout. The items below are a few correlations that stood out for 91302, not a ranked or complete list of what matters most.
Areas with high college attainment vote Democratic. About 72% of adults in 91302 hold a bachelor's degree, about 44 points above the U.S. average of 28%.
Population density and Democratic lean
Places with high population density tend to lean Democratic; 91302, CA sits in the top quarter nationally on this measure.
Why turnout in 91302 looks the way it does
Areas with strong routine healthcare access turn out at higher rates. 91302 is in the top quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. The dental-visit rate here is about 76%, about 16 points above the U.S. average of 60%. High high-school completion lines up with higher turnout, and about 99% of adults in 91302 have completed high school, above 97% of zip codes. Learn more about the findings and methodology on the political spectrum map.
Nearby Zip Codes
Zip Codes with Similar Populations
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.