Boone County leans Republican by roughly 16 points: about 42% of voters vote Democratic and 58% Republican.
About 75% of adults in Boone County typically vote, above the U.S. average of about 62%. Among adults in Boone County, ~32% vote Democratic, ~44% Republican, and ~24% don't vote. The map below shows estimated turnout by block group.
How Boone County compares
Among counties within 50 miles, Boone County leans more Republican than 8 of 11 neighbors.
Boone County runs about 26 points more Republican than Illinois as a whole. Illinois leans Democratic overall, while Boone County is one of the few Republican-leaning pockets.
Politics vary noticeably by city within Boone County. The southwest side is the most Republican-leaning (R+31) and the south side is the least Republican-leaning (R+4), a spread of about 27 points.
Why Boone 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 Boone County, not a ranked or complete list of what matters most.
Boone County votes Republican even though it is densely developed (about 55%, well above the Illinois average of 33%). State and regional patterns outweigh the Democratic lean that density usually predicts here. A high family-household share predicts Republican voting, and about 74% of households in Boone County are family households, above 93% of counties. Boone County runs against the grain of Illinois, a Republican-leaning pocket in a Democratic-leaning state.
Population density and Democratic lean
Places with high population density tend to lean Democratic; Boone County, IL sits in the top quarter nationally on this measure.
Why turnout in Boone County looks the way it does
Homeowners vote more often than renters. About 83% of households in Boone County own their home, about 8 points above the U.S. average of 75%. Learn more about the findings and methodology on the political spectrum map.
Nearby Counties
- Winnebago County, IL D+7
- McHenry County, IL R+5
- DeKalb County, IL D+3
- Rock County, WI Even
- Ogle County, IL R+28
- Walworth County, WI R+17
- Kane County, IL D+13
- Stephenson County, IL R+14
- Lee County, IL R+21
- Lake County, IL D+22
Counties with Similar Populations
- Coffee County, AL R+46
- Roane County, TN R+57
- Fulton County, NY R+28
- Tuscola County, MI R+42
- McMinn County, TN R+61
- Gila County, AZ R+27
- Elko County, NV R+46
- Jessamine County, KY R+35
- Jackson County, IL D+7
- Washington County, VA R+52
All Local Stats
Home Services
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.