Summersville is a Republican stronghold. About 24% of voters here vote Democratic and 76% Republican.
About 75% of adults in Summersville typically vote, above the U.S. average of about 62%. Among adults in Summersville, ~18% vote Democratic, ~57% Republican, and ~25% don't vote. The map below shows estimated turnout by block group.
How Summersville compares
Among cities within 25 miles, Summersville leans more Republican than 8 of 66 neighbors.
Summersville runs about 62 points more Republican than Illinois as a whole. Illinois leans Democratic overall, while Summersville is one of the few Republican-leaning pockets.
Why Summersville 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 Summersville, not a ranked or complete list of what matters most.
Summersville votes against the grain of Illinois. Illinois leans Democratic overall, while Summersville runs about 62 points more Republican.
Preventive-care access and voter turnout
Places with strong routine preventive-care access tend to turn out at a higher rate; Summersville, IL sits above the national average on this measure. Dental visits do not drive turnout; the rate reflects income, insurance, and healthcare access, which line up with who votes.
Why turnout in Summersville looks the way it does
Homeowners vote more often than renters. About 90% of households in Summersville own their home, about 11 points above the Illinois average of 80%. High high-school completion lines up with higher turnout, and about 96% of adults in Summersville have completed high school, above 86% of cities. Learn more about the findings and methodology on the political spectrum map.
Nearby Cities
- Mount Vernon, IL R+30
- Idlewood, IL R+46
- Camp Ground, IL R+60
- Opdyke, IL R+67
- Texico, IL R+65
- Bluford, IL R+68
- Marcoe, IL R+49
- Dix, IL R+59
- Woodlawn, IL R+57
- Bonnie, IL R+64
Cities with Similar Populations
- Silver City, ID R+74
- Mitchellsville, NY R+28
- Bradley, MS R+51
- Fosheeton, AL R+71
- Mount Herman, OK R+83
- Blanchard, IA R+57
- Lee Center, IL R+39
- Natrona, WY R+81
- Fraleytown, VA R+77
- Lemoore Naval Air Station, CA R+37
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.