94121 is a Democratic stronghold. About 79% of voters here vote Democratic and 21% Republican.
About 66% of adults in 94121 typically vote, near the U.S. average of about 62%. Among adults in 94121, ~52% vote Democratic, ~14% Republican, and ~34% don't vote. The map below shows estimated turnout by block group.
How 94121 compares
Among zip codes within 15 miles, 94121 leans more Democratic than 33 of 72 neighbors.
94121 runs about 38 points more Democratic than California as a whole.
Politics vary noticeably by block within 94121. The east side is the most Democratic-leaning (D+64) and the northwest side is the least Democratic-leaning (D+48), a spread of about 16 points.
Why 94121 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 94121, not a ranked or complete list of what matters most.
Dense areas vote Democratic. About 95% of residents in 94121 live in densely developed areas, about 59 points above the U.S. average of 36%. High college attainment predicts Democratic voting, and 94121 sits in the top quarter (about 65%, above 96% of zip codes). A high never-married share predicts Democratic voting, and about 38% of adults in 94121 have never been married, above 84% of zip codes.
Walkability and Democratic lean
Places with a highly walkable street grid tend to lean Democratic; 94121, 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 94121 looks the way it does
Areas with strong routine healthcare access turn out at higher rates. 94121 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 70%, about 10 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.