Caseyville leans slightly Republican by roughly 8 points: about 46% of voters vote Democratic and 54% Republican.
About 75% of adults in Caseyville typically vote, above the U.S. average of about 62%. Among adults in Caseyville, ~34% vote Democratic, ~41% Republican, and ~25% don't vote. The map below shows estimated turnout by block group.
How Caseyville compares
Among cities within 25 miles, Caseyville leans more Republican than 102 of 164 neighbors.
Caseyville runs about 19 points more Republican than Illinois as a whole. Illinois leans Democratic overall, while Caseyville is one of the few Republican-leaning pockets.
Politics vary noticeably by neighborhood within Caseyville. The southwest side runs the most Democratic (D+6) and the south side runs the most Republican (R+17), a spread of about 23 points.
Why Caseyville 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 Caseyville, not a ranked or complete list of what matters most.
Caseyville votes Republican even though it is densely developed (about 46%, modestly above the Illinois average of 33%). State and regional patterns outweigh the Democratic lean that density usually predicts here. Caseyville runs against the grain of Illinois, a Republican-leaning pocket in a Democratic-leaning state.
Preventive-care access and voter turnout
Places with strong routine preventive-care access tend to turn out at a higher rate; Caseyville, 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 Caseyville looks the way it does
Turnout in Caseyville sits close to the national pattern. Routine healthcare access, homeownership, education, and food security all land near their national averages here. Learn more about the findings and methodology on the political spectrum map.
Nearby Cities
- State Park Place, IL D+12
- Fairview Heights, IL D+18
- Collinsville, IL Even
- Washington Park, IL D+63
- Meadow Heights, IL R+20
- Lumaghi Heights, IL R+20
- Fairmont City, IL D+6
- O'Fallon, IL D+8
- Swansea, IL D+10
- East St. Louis, IL D+83
Cities with Similar Populations
- Northwest Harborcreek, PA R+5
- Breckenridge, CO D+24
- Milan, IL R+9
- Halfway, MD R+24
- Needville, TX R+50
- Newport, AR R+38
- Montecito, CA D+40
- Island Lake, IL R+8
- Piney Flats, TN R+55
- Kaplan, LA R+59
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.