Irwindale leans Democratic by roughly 24 points: about 62% of voters vote Democratic and 38% Republican.
About 30% of adults in Irwindale typically vote, below the U.S. average of about 62%. Among adults in Irwindale, ~19% vote Democratic, ~11% Republican, and ~70% don't vote. The map below shows estimated turnout by block group.
How Irwindale compares
Among cities within 25 miles, Irwindale leans more Democratic than 67 of 112 neighbors.
Irwindale runs about 4 points more Democratic than California as a whole.
Why Irwindale leans the way it does
This analysis examined 14,881 data points per city to find what predicts political lean and turnout. The items below are a few correlations that stood out for Irwindale, not a ranked or complete list of what matters most.
Dense areas vote Democratic. About 80% of residents in Irwindale live in densely developed areas, about 44 points above the U.S. average of 36%. A high never-married share predicts Democratic voting, and about 38% of adults in Irwindale have never been married, above 92% of cities.
Paved land cover and Democratic lean
Places with extensive paved surfaces tend to lean Democratic; Irwindale, 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 Irwindale looks the way it does
Areas with limited routine healthcare access turn out at lower rates. Irwindale is in the bottom quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. Crowded housing lines up with lower turnout, and about 4% of homes in Irwindale have more than one occupant per room, above 85% of cities. Learn more about the findings and methodology on the political spectrum map.
Nearby Cities
- Vincent, CA D+22
- Baldwin Park, CA D+28
- Duarte, CA D+24
- Azusa, CA D+22
- Bradbury, CA D+4
- Citrus, CA D+22
- West Covina, CA D+20
- Covina, CA D+14
- West Puente Valley, CA D+30
- Monrovia, CA D+27
Cities with Similar Populations
- Bradley, ME R+34
- Gold, TX R+59
- Bryant, IN R+71
- Paullina, IA R+58
- Mason, WV R+53
- Bentonia, MS R+40
- Laurens, IA R+47
- Polk, PA R+50
- Milford, TX R+59
- Sturgis, MS R+49
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.