Henderson County leans heavily Republican by roughly 40 points: about 30% of voters vote Democratic and 70% Republican.
About 75% of adults in Henderson County typically vote, above the U.S. average of about 62%. Among adults in Henderson County, ~22% vote Democratic, ~52% Republican, and ~26% don't vote. The map below shows estimated turnout by block group.
How Henderson County compares
Among counties within 50 miles, Henderson County leans more Republican than 10 of 12 neighbors.
Henderson County runs about 52 points more Republican than Illinois as a whole. Illinois leans Democratic overall, while Henderson County is one of the few Republican-leaning pockets.
Politics vary noticeably by city within Henderson County. The southeast side is the most Republican-leaning (R+51) and the northwest side is the least Republican-leaning (R+31), a spread of about 20 points.
Why Henderson County leans the way it does
This analysis examined 14,881 data points per county to find what predicts political lean and turnout. The items below are a few correlations that stood out for Henderson County, not a ranked or complete list of what matters most.
Rural areas vote Republican. About 7% of residents in Henderson County live in densely developed areas, about 26 points below the Illinois average of 33%. Henderson County runs against the grain of Illinois, a Republican-leaning pocket in a Democratic-leaning state.
Walkability and Republican lean
Places with a low walkability score tend to lean Republican; Henderson County, IL sits in the bottom tenth nationally on this measure. A walkable street grid does not change how people vote; it mostly reflects how urban a place is.
Why turnout in Henderson County looks the way it does
Turnout in Henderson County sits close to the national pattern. Learn more about the findings and methodology on the political spectrum map.
Nearby Counties
- Des Moines County, IA R+8
- Warren County, IL R+22
- McDonough County, IL R+11
- Lee County, IA R+27
- Mercer County, IL R+33
- Hancock County, IL R+45
- Louisa County, IA R+37
- Henry County, IA R+31
- Knox County, IL R+9
- Muscatine County, IA R+16
Counties with Similar Populations
- Bottineau County, ND R+50
- Ellsworth County, KS R+56
- Bear Lake County, ID R+71
- Treutlen County, GA R+35
- Saguache County, CO D+5
- Spink County, SD R+50
- Randolph County, GA D+3
- Moody County, SD R+40
- Norman County, MN R+27
- Moore County, TN R+69
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.