91915 leans Democratic by roughly 16 points: about 58% of voters vote Democratic and 42% Republican.
About 67% of adults in 91915 typically vote, near the U.S. average of about 62%. Among adults in 91915, ~39% vote Democratic, ~28% Republican, and ~33% don't vote. The map below shows estimated turnout by block group.
How 91915 compares
Among zip codes within 15 miles, 91915 leans more Democratic than 14 of 39 neighbors.
Politically, 91915 sits close to the rest of California.
Why 91915 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 91915, not a ranked or complete list of what matters most.
Dense areas vote Democratic. About 82% of residents in 91915 live in densely developed areas, about 46 points above the U.S. average of 36%. High college attainment predicts Democratic voting, and 91915 sits in the top quarter (about 52%, above 90% of zip codes).
Population density and Democratic lean
Places with high population density tend to lean Democratic; 91915, CA sits in the top tenth nationally on this measure.
Why turnout in 91915 looks the way it does
Turnout in 91915 sits close to the national pattern. Routine healthcare access, homeownership, education, and food security all land near their national averages here. 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.