San Dimas is a true toss-up. About 52% of voters here vote Democratic and 48% Republican.
About 67% of adults in San Dimas typically vote, near the U.S. average of about 62%. Among adults in San Dimas, ~35% vote Democratic, ~32% Republican, and ~33% don't vote. The map below shows estimated turnout by block group.
How San Dimas compares
Among cities within 25 miles, San Dimas leans more Democratic than 30 of 105 neighbors.
San Dimas runs about 16 points more Republican than California as a whole.
Politics vary noticeably by neighborhood within San Dimas. The east side runs the most Democratic (D+12) and the south side runs the most Republican (R+6), a spread of about 19 points.
Why San Dimas leans the way it does
Density, race composition, education, and family structure all sit close to their national averages in San Dimas. The lean here lands roughly where demographic data alone would predict.
Paved land cover and Democratic lean
Places with extensive paved surfaces tend to lean Democratic; San Dimas, 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 San Dimas looks the way it does
Areas with strong routine healthcare access turn out at higher rates. San Dimas 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 68%, about 7 points above the U.S. average of 60%. Learn more about the findings and methodology on the political spectrum map.
Nearby Cities
- La Verne, CA D+3
- Glendora, CA Even
- Covina, CA D+14
- Citrus, CA D+22
- Pomona, CA D+28
- Azusa, CA D+22
- Walnut, CA D+10
- Claremont, CA D+34
- Vincent, CA D+22
- West Covina, CA D+20
Cities with Similar Populations
- Wappingers Falls, NY R+4
- Manor, TX D+30
- Adrian, MI R+13
- Merrillville, IN D+47
- Lemoore, CA R+15
- Southampton, PA R+8
- Riviera Beach, FL D+50
- Severn, MD D+34
- Gahanna, OH D+21
- Saratoga Springs, NY D+23
All Local Stats
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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.