91917 leans Republican by roughly 28 points: about 36% of voters vote Democratic and 64% Republican.
About 30% of adults in 91917 typically vote, below the U.S. average of about 62%. Among adults in 91917, ~11% vote Democratic, ~19% Republican, and ~70% don't vote. The map below shows estimated turnout by block group.
How 91917 compares
Among zip codes within 15 miles, 91917 leans more Republican than 8 of 10 neighbors.
91917 runs about 49 points more Republican than California as a whole. California leans Democratic overall, while 91917 is one of the few Republican-leaning pockets.
Politics vary noticeably by block within 91917. The west side is the most Republican-leaning (R+29) and the southeast side is the least Republican-leaning (R+14), a spread of about 15 points.
Why 91917 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 91917, not a ranked or complete list of what matters most.
91917 votes against the grain of California. California leans Democratic overall, while 91917 runs about 49 points more Republican. Rural areas vote Republican, and 91917 sits in the bottom quarter on density (about 2%, below 97% of zip codes).
Paved land cover and Republican lean
Places with little paved surface tend to lean Republican; 91917, CA sits in the bottom 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 91917 looks the way it does
Areas with limited routine healthcare access turn out at lower rates. 91917 is in the bottom quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. Low high-school completion lines up with lower turnout, and about 70% of adults in 91917 have completed high school, below 98% 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.