Sumner is a Republican stronghold. About 24% of voters here vote Democratic and 76% Republican.
About 60% of adults in Sumner typically vote, near the U.S. average of about 62%. Among adults in Sumner, ~14% vote Democratic, ~46% Republican, and ~40% don't vote. The map below shows estimated turnout by block group.
How Sumner compares
Among cities within 25 miles, Sumner leans more Republican than 9 of 59 neighbors.
Sumner runs about 63 points more Republican than Illinois as a whole. Illinois leans Democratic overall, while Sumner is one of the few Republican-leaning pockets.
Politics vary noticeably by neighborhood within Sumner. The southwest side is the most Republican-leaning (R+66) and the west side is the least Republican-leaning (R+35), a spread of about 31 points.
Why Sumner 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 Sumner, not a ranked or complete list of what matters most.
Sumner votes against the grain of Illinois. Illinois leans Democratic overall, while Sumner runs about 63 points more Republican. Low college attainment predicts Republican voting, and Sumner sits in the bottom quarter (about 12%, below 87% of cities).
Preventive-care access and voter turnout
Places with limited routine preventive-care access tend to turn out at a lower rate; Sumner, IL sits below 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 Sumner looks the way it does
Areas with low high-school completion turn out at lower rates. About 83% of adults in Sumner have completed high school, about 7 points below the U.S. average of 90%. Learn more about the findings and methodology on the political spectrum map.
Nearby Cities
- Claremont, IL R+32
- Petrolia, IL R+62
- Bridgeport, IL R+58
- Birds, IL R+56
- Helena, IL R+70
- Landes, IL R+67
- Lawrenceville, IL R+42
- Calhoun, IL R+68
- Port Jackson, IL R+65
- Pinkstaff, IL R+60
Cities with Similar Populations
- Tioga, PA R+57
- Durham, FL R+20
- Bullock, NC R+26
- Galeton, PA R+50
- Marydel, DE R+51
- Hurley, NM R+13
- Terrell, NC R+39
- Henry, VA R+57
- Landen, OH R+8
- Laona, WI R+37
All Local Stats
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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.