91702 leans Democratic by roughly 22 points: about 61% of voters vote Democratic and 39% Republican.
About 46% of adults in 91702 typically vote, below the U.S. average of about 62%. Among adults in 91702, ~28% vote Democratic, ~18% Republican, and ~54% don't vote. The map below shows estimated turnout by block group.
How 91702 compares
Among zip codes within 15 miles, 91702 leans more Democratic than 35 of 66 neighbors.
Politically, 91702 sits close to the rest of California.
Politics vary noticeably by block within 91702. The south side is the most Democratic-leaning (D+28) and the northeast side is the least Democratic-leaning (D+13), a spread of about 15 points.
Why 91702 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 91702, not a ranked or complete list of what matters most.
Dense areas vote Democratic. About 95% of residents in 91702 live in densely developed areas, about 59 points above the U.S. average of 36%. A high never-married share predicts Democratic voting, and about 46% of adults in 91702 have never been married, above 92% of zip codes.
Paved land cover and Democratic lean
Places with extensive paved surfaces tend to lean Democratic; 91702, CA sits in the top tenth 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 91702 looks the way it does
Areas with limited routine healthcare access turn out at lower rates. 91702 is in the bottom quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. Renters vote less often than owners, and about 40% of households in 91702 rent, about 15 points above the U.S. average of 25%. High food insecurity lines up with lower turnout, and about 24% of adults in 91702 report food insecurity, above 88% 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.