91381 leans slightly Democratic by roughly 6 points: about 53% of voters vote Democratic and 47% Republican.
About 59% of adults in 91381 typically vote, near the U.S. average of about 62%. Among adults in 91381, ~31% vote Democratic, ~28% Republican, and ~41% don't vote. The map below shows estimated turnout by block group.
How 91381 compares
Among zip codes within 15 miles, 91381 leans more Democratic than 7 of 32 neighbors.
91381 runs about 14 points more Republican than California as a whole.
Politics vary noticeably by block within 91381. The east side runs the most Democratic (D+12) and the southwest side runs the most Republican (R+9), a spread of about 21 points.
Why 91381 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 91381, not a ranked or complete list of what matters most.
Areas with high college attainment vote Democratic. About 59% of adults in 91381 hold a bachelor's degree, about 31 points above the U.S. average of 28%. Density combined with diversity predicts Democratic voting, and non-Hispanic white share in 91381 is about 41%, about 31 points below the U.S. average of 72%.
Cancer-screening access and voter turnout
Places with low colon-cancer-screening access tend to turn out at a lower rate; 91381, CA sits in the bottom tenth nationally on this measure. Cancer screening does not drive turnout; it reflects income, insurance, and healthcare access.
Why turnout in 91381 looks the way it does
Renters vote less often than owners. About 35% of households in 91381 rent, about 10 points above the U.S. average of 25%. Strong routine healthcare access lines up with higher turnout, and 91381 sits in the top quarter on routine-care measures. 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.