90278 leans Democratic by roughly 28 points: about 64% of voters vote Democratic and 36% Republican.
About 72% of adults in 90278 typically vote, above the U.S. average of about 62%. Among adults in 90278, ~46% vote Democratic, ~26% Republican, and ~28% don't vote. The map below shows estimated turnout by block group.
How 90278 compares
Among zip codes within 15 miles, 90278 leans more Democratic than 20 of 111 neighbors.
90278 runs about 8 points more Democratic than California as a whole.
Politics vary noticeably by block within 90278. The east side is the most Democratic-leaning (D+35) and the south side is the least Democratic-leaning (D+18), a spread of about 17 points.
Why 90278 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 90278, not a ranked or complete list of what matters most.
Dense areas vote Democratic. More than 99% of residents in 90278 live in densely developed areas, about 64 points above the U.S. average of 36%. High college attainment predicts Democratic voting, and 90278 sits in the top quarter (about 64%, above 96% of zip codes).
Walkability and Democratic lean
Places with a highly walkable street grid tend to lean Democratic; 90278, 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 90278 looks the way it does
Areas with strong routine healthcare access turn out at higher rates. 90278 is in the top quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. The dental-visit rate here is about 73%, about 13 points above the U.S. average of 60%. 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.