90031 leans heavily Democratic by roughly 42 points: about 71% of voters vote Democratic and 29% Republican.
About 38% of adults in 90031 typically vote, below the U.S. average of about 62%. Among adults in 90031, ~27% vote Democratic, ~11% Republican, and ~62% don't vote. The map below shows estimated turnout by block group.
How 90031 compares
Among zip codes within 15 miles, 90031 leans more Democratic than 82 of 161 neighbors.
90031 runs about 23 points more Democratic than California as a whole.
Politics vary noticeably by block within 90031. The southwest side is the most Democratic-leaning (D+55) and the northwest side is the least Democratic-leaning (D+39), a spread of about 17 points.
Why 90031 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 90031, not a ranked or complete list of what matters most.
Dense areas vote Democratic. About 98% of residents in 90031 live in densely developed areas, about 62 points above the U.S. average of 36%. A high never-married share predicts Democratic voting, and about 46% of adults in 90031 have never been married, above 92% of zip codes.
Paved land cover and Democratic lean
Places with extensive paved surfaces tend to lean Democratic; 90031, 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 90031 looks the way it does
Areas with limited routine healthcare access turn out at lower rates. 90031 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 69% of households in 90031 rent, about 44 points above the U.S. average of 25%. High food insecurity lines up with lower turnout, and about 31% of adults in 90031 report food insecurity, above 94% 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.