91934 leans heavily Republican by roughly 32 points: about 34% of voters vote Democratic and 66% Republican.
About 25% of adults in 91934 typically vote, below the U.S. average of about 62%. Among adults in 91934, ~9% vote Democratic, ~17% Republican, and ~74% don't vote. The map below shows estimated turnout by block group.
How 91934 compares
91934 sits in a sparsely populated area with few comparable zip codes nearby.
91934 runs about 52 points more Republican than California as a whole. California leans Democratic overall, while 91934 is one of the few Republican-leaning pockets.
Why 91934 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 91934, not a ranked or complete list of what matters most.
91934 votes against the grain of California. California leans Democratic overall, while 91934 runs about 52 points more Republican. Low college attainment predicts Republican voting, and 91934 sits in the bottom quarter (about 15%, below 82% of zip codes). A high family-household share predicts Republican voting, and about 83% of households in 91934 are family households, above 95% of zip codes.
Paved land cover and Republican lean
Places with little paved surface tend to lean Republican; 91934, CA sits in the bottom quarter nationally on this measure. Paved ground does not change how people vote; it mostly reflects how urban and built-up a place is.
Why turnout in 91934 looks the way it does
Renters vote less often than owners. About 70% of households in 91934 rent, about 45 points above the U.S. average of 25%. Low high-school completion lines up with lower turnout, and more than 99% of adults in 91934 have completed high school, in the top fraction of zip codes. High-crime urban areas turn out at lower rates, and 91934 sits in the top 15% on a violent-crime measure. 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.