Madison leans heavily Democratic by roughly 40 points: about 70% of voters vote Democratic and 30% Republican.
About 55% of adults in Madison typically vote, below the U.S. average of about 62%. Among adults in Madison, ~38% vote Democratic, ~17% Republican, and ~45% don't vote. The map below shows estimated turnout by block group.
How Madison compares
Among cities within 25 miles, Madison leans more Democratic than 118 of 171 neighbors.
Madison runs about 28 points more Democratic than Illinois as a whole.
Politics vary noticeably by neighborhood within Madison. The southwest side runs the most Democratic (D+83) and the northeast side runs the most Republican (R+38), a spread of about 121 points.
Why Madison 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 Madison, not a ranked or complete list of what matters most.
Dense areas vote Democratic. About 77% of residents in Madison live in densely developed areas, about 41 points above the U.S. average of 36%. A high never-married share predicts Democratic voting, and about 42% of adults in Madison have never been married, above 95% of cities.
Preventive-care access and voter turnout
Places with limited routine preventive-care access tend to turn out at a lower rate; Madison, IL sits in the bottom quarter nationally 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 Madison looks the way it does
Renters vote less often than owners. About 44% of households in Madison rent, about 19 points above the U.S. average of 25%. Limited routine healthcare access lines up with lower turnout, and Madison sits in the bottom quarter on routine-care measures. High food insecurity lines up with lower turnout, and about 30% of adults in Madison report food insecurity, above 95% of cities. Learn more about the findings and methodology on the political spectrum map.
Nearby Cities
- Venice, IL D+87
- Lovejoy, IL D+74
- Brooklyn, IL D+85
- Granite City, IL R+13
- Fairmont City, IL D+6
- Washington Park, IL D+63
- Pontoon Beach, IL R+22
- Riverview, MO D+69
- East St. Louis, IL D+83
- Bellefontaine Neighbors, MO D+79
Cities with Similar Populations
- Howey-in-the-Hills, FL R+52
- Oriskany, NY R+10
- Snow Hill, MD Even
- Anderson, MO R+68
- Deer Lodge, MT R+44
- Loretto, PA R+50
- Muttontown, NY R+11
- Mariemont, OH D+27
- West Sayville, NY R+18
- Waymart, PA R+42
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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.