Rosemont leans Democratic by roughly 20 points: about 60% of voters vote Democratic and 40% Republican.
About 61% of adults in Rosemont typically vote, near the U.S. average of about 62%. Among adults in Rosemont, ~37% vote Democratic, ~24% Republican, and ~39% don't vote. The map below shows estimated turnout by block group.
How Rosemont compares
Among cities within 25 miles, Rosemont leans more Democratic than 49 of 58 neighbors.
Politically, Rosemont sits close to the rest of California.
Politics vary noticeably by neighborhood within Rosemont. The northwest side is the most Democratic-leaning (D+36) and the southwest side is the least Democratic-leaning (D+13), a spread of about 23 points.
Why Rosemont 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 Rosemont, not a ranked or complete list of what matters most.
Dense areas vote Democratic. About 98% of residents in Rosemont live in densely developed areas, about 62 points above the U.S. average of 36%. A high never-married share predicts Democratic voting, and about 37% of adults in Rosemont have never been married, above 91% of cities.
Population density and Democratic lean
Places with high population density tend to lean Democratic; Rosemont, CA sits in the top tenth nationally on this measure.
Why turnout in Rosemont looks the way it does
Renters vote less often than owners. About 37% of households in Rosemont rent, about 12 points above the U.S. average of 25%. Crowded housing lines up with lower turnout, and about 5% of homes in Rosemont have more than one occupant per room, above 86% of cities. Learn more about the findings and methodology on the political spectrum map.
Nearby Cities
- La Riviera, CA D+30
- Mather, CA Even
- Arden-Arcade, CA D+25
- Rancho Cordova, CA D+10
- Lemon Hill, CA D+33
- Florin, CA D+25
- Vineyard, CA D+12
- Carmichael, CA D+11
- Parkway, CA D+35
- Sacramento, CA D+14
Cities with Similar Populations
- Westford, MA D+25
- Gettysburg, PA R+12
- Crescent City, CA R+15
- Watertown, SD R+40
- Maywood, IL D+74
- Hayesville, OR D+9
- Kennett Square, PA D+18
- Newton, MA D+58
- Brambleton, VA D+22
- Lynn Haven, FL R+36
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.