90003 is a Democratic stronghold. About 75% of voters here vote Democratic and 25% Republican.
About 31% of adults in 90003 typically vote, below the U.S. average of about 62%. Among adults in 90003, ~23% vote Democratic, ~8% Republican, and ~69% don't vote. The map below shows estimated turnout by block group.
How 90003 compares
Among zip codes within 15 miles, 90003 leans more Democratic than 120 of 172 neighbors.
90003 runs about 30 points more Democratic than California as a whole.
Why 90003 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 90003, not a ranked or complete list of what matters most.
Dense areas vote Democratic. More than 99% of residents in 90003 live in densely developed areas, about 64 points above the U.S. average of 36%. A high never-married share predicts Democratic voting, and about 54% of adults in 90003 have never been married, above 96% of zip codes.
Walkability and Democratic lean
Places with a highly walkable street grid tend to lean Democratic; 90003, 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 90003 looks the way it does
Areas with limited routine healthcare access turn out at lower rates. 90003 is in the bottom quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. The dental-visit rate here is about 42%, about 20 points below the California average of 62%. Renters vote less often than owners, and about 72% of households in 90003 rent, about 47 points above the U.S. average of 25%. High food insecurity lines up with lower turnout, and about 46% of adults in 90003 report food insecurity, in the top fraction 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.