Rochester leans Republican by roughly 28 points: about 36% of voters vote Democratic and 64% Republican.
About 95% of adults in Rochester typically vote, above the U.S. average of about 62%. Among adults in Rochester, ~34% vote Democratic, ~61% Republican, and ~5% don't vote. The map below shows estimated turnout by block group.
How Rochester compares
Among cities within 25 miles, Rochester leans more Republican than 10 of 69 neighbors.
Rochester runs about 38 points more Republican than Illinois as a whole. Illinois leans Democratic overall, while Rochester is one of the few Republican-leaning pockets.
Politics vary noticeably by neighborhood within Rochester. The south side is the most Republican-leaning (R+39) and the west side is the least Republican-leaning (R+18), a spread of about 20 points.
Why Rochester 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 Rochester, not a ranked or complete list of what matters most.
Rochester votes against the grain of Illinois. Illinois leans Democratic overall, while Rochester runs about 38 points more Republican. A high family-household share predicts Republican voting, and about 77% of households in Rochester are family households, above 81% of cities.
Walkability and Republican lean
Places with a low walkability score tend to lean Republican; Rochester, IL sits in the bottom quarter 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 Rochester looks the way it does
Areas with strong routine healthcare access turn out at higher rates. Rochester 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%. Homeowners vote more often than renters, and about 94% of households in Rochester own their home, compared to around 79% in nearby cities. High high-school completion lines up with higher turnout, and about 99% of adults in Rochester have completed high school, above 98% of cities. Learn more about the findings and methodology on the political spectrum map.
Nearby Cities
- New City, IL R+40
- Clear Lake, IL R+31
- Roby, IL R+44
- Southern View, IL R+6
- Dawson, IL R+46
- Springfield, IL D+14
- Riverton, IL R+26
- Jerome, IL D+16
- Mechanicsburg, IL R+49
- Bissell, IL R+29
Cities with Similar Populations
- East Moriches, NY R+24
- Clinton, NJ D+5
- Millers Creek, NC R+65
- Waialua, HI D+20
- Coxs Creek, KY R+51
- Elkview, WV R+50
- North Fort Lewis, WA R+5
- Norwood, PA R+5
- Wendell, ID R+53
- Solon, IA Even
Sources and methodology
Precinct-level voting records used to fit the model come from Illinois State Board of 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.