90631 is a true toss-up. About 52% of voters here vote Democratic and 48% Republican.
About 57% of adults in 90631 typically vote, near the U.S. average of about 62%. Among adults in 90631, ~30% vote Democratic, ~28% Republican, and ~42% don't vote. The map below shows estimated turnout by block group.
How 90631 compares
Among zip codes within 15 miles, 90631 leans more Democratic than 25 of 110 neighbors.
90631 runs about 16 points more Republican than California as a whole.
Politics vary noticeably by block within 90631. The east side runs the most Democratic (D+11) and the northwest side runs the most Republican (R+6), a spread of about 17 points.
Why 90631 leans the way it does
Density, race composition, education, and family structure all sit close to their national averages in 90631. The lean here lands roughly where demographic data alone would predict.
Walkability and Democratic lean
Places with a highly walkable street grid tend to lean Democratic; 90631, CA sits in the top tenth nationally on this measure. A walkable street grid does not change how people vote; it mostly reflects how urban a place is.
Why turnout in 90631 looks the way it does
Areas with limited routine healthcare access turn out at lower rates. 90631 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 39% of households in 90631 rent, above 86% of zip codes. Crowded housing lines up with lower turnout, and about 11% of homes in 90631 have more than one occupant per room, above 96% 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.