91733 leans Democratic by roughly 28 points: about 64% of voters vote Democratic and 36% Republican.
About 35% of adults in 91733 typically vote, below the U.S. average of about 62%. Among adults in 91733, ~22% vote Democratic, ~13% Republican, and ~65% don't vote. The map below shows estimated turnout by block group.
How 91733 compares
Among zip codes within 15 miles, 91733 leans more Democratic than 71 of 127 neighbors.
91733 runs about 8 points more Democratic than California as a whole.
Politics vary noticeably by block within 91733. The east side is the most Democratic-leaning (D+36) and the south side is the least Democratic-leaning (D+22), a spread of about 14 points.
Why 91733 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 91733, not a ranked or complete list of what matters most.
Dense areas vote Democratic. More than 99% of residents in 91733 live in densely developed areas, about 63 points above the U.S. average of 36%. A high never-married share predicts Democratic voting, and about 46% of adults in 91733 have never been married, above 93% of zip codes.
Preventive-care access and voter turnout
Places with limited routine preventive-care access tend to turn out at a lower rate; 91733, CA sits in the bottom tenth nationally on this measure. Dental visits do not drive turnout; the rate reflects income, insurance, and healthcare access, which line up with who votes.
Why turnout in 91733 looks the way it does
Areas with limited routine healthcare access turn out at lower rates. 91733 is in the bottom quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. The dental-visit rate here is about 47%, about 15 points below the California average of 62%. Renters vote less often than owners, and about 58% of households in 91733 rent, about 33 points above the U.S. average of 25%. High food insecurity lines up with lower turnout, and about 36% of adults in 91733 report food insecurity, 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.