Glen Carbon is a true toss-up. About 52% of voters here vote Democratic and 48% Republican.
About 88% of adults in Glen Carbon typically vote, above the U.S. average of about 62%. Among adults in Glen Carbon, ~46% vote Democratic, ~42% Republican, and ~12% don't vote. The map below shows estimated turnout by block group.
How Glen Carbon compares
Among cities within 25 miles, Glen Carbon leans more Democratic than 70 of 153 neighbors.
Glen Carbon runs about 7 points more Republican than Illinois as a whole.
Politics vary noticeably by neighborhood within Glen Carbon. The east side runs the most Democratic (D+8) and the southwest side runs the most Republican (R+3), a spread of about 11 points.
Why Glen Carbon leans the way it does
Density, race composition, education, and family structure all sit close to their national averages in Glen Carbon. The lean here lands roughly where demographic data alone would predict.
Population density and Democratic lean
Places with high population density tend to lean Democratic; Glen Carbon, IL sits in the top quarter nationally on this measure.
Why turnout in Glen Carbon looks the way it does
Areas with strong routine healthcare access turn out at higher rates. Glen Carbon 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 71%, about 11 points above the U.S. average of 60%. High high-school completion lines up with higher turnout, and about 97% of adults in Glen Carbon have completed high school, above 92% of cities. Learn more about the findings and methodology on the political spectrum map.
Nearby Cities
- Maryville, IL R+10
- Edwardsville, IL D+6
- Poag, IL D+4
- Meadow Heights, IL R+20
- Kuhn Station, IL R+34
- Troy, IL R+25
- Wanda, IL R+29
- Collinsville, IL Even
- Pontoon Beach, IL R+22
- Lumaghi Heights, IL R+20
Cities with Similar Populations
- Seabrook, TX R+27
- New Carrollton, MD D+70
- Chester, SC D+5
- Discovery Bay, CA R+12
- Goffstown, NH Even
- Dumas, TX R+33
- Shively, KY D+53
- King City, CA D+14
- Upper Marlboro, MD D+76
- Rocky Mount, VA R+36
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.