Brown County leans heavily Republican by roughly 38 points: about 31% of voters vote Democratic and 69% Republican.
About 66% of adults in Brown County typically vote, near the U.S. average of about 62%. Among adults in Brown County, ~20% vote Democratic, ~46% Republican, and ~34% don't vote. The map below shows estimated turnout by block group.
How Brown County compares
Among counties within 50 miles, Brown County leans more Republican than 3 of 14 neighbors.
Brown County runs about 50 points more Republican than Illinois as a whole. Illinois leans Democratic overall, while Brown County is one of the few Republican-leaning pockets.
Politics vary noticeably by city within Brown County. The south side is the most Republican-leaning (R+62) and the north side is the least Republican-leaning (R+31), a spread of about 31 points.
Why Brown 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 Brown County, not a ranked or complete list of what matters most.
Areas with low college attainment vote Republican. About 13% of adults in Brown County hold a bachelor's degree, about 13 points below the Illinois average of 27%. Car-dependent areas vote Republican, and about 84% of residents in Brown County drive to work alone, above 92% of counties. Brown County runs against the grain of Illinois, a Republican-leaning pocket in a Democratic-leaning state.
Park access and Republican lean
Places with low park coverage tend to lean Republican; Brown County, IL sits in the bottom quarter nationally on this measure. Park access does not change how people vote; it tends to track denser, higher-income areas.
Why turnout in Brown County looks the way it does
Turnout in Brown County 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 Counties
- Schuyler County, IL R+44
- Cass County, IL R+31
- Pike County, IL R+57
- Scott County, IL R+64
- Adams County, IL R+40
- Morgan County, IL R+25
- McDonough County, IL R+11
- Hancock County, IL R+45
- Marion County, MO R+44
- Greene County, IL R+56
Counties with Similar Populations
- Edwards County, IL R+64
- Pawnee County, KS R+49
- Calhoun County, WV R+65
- Teton County, MT R+60
- Woodruff County, AR R+40
- Bland County, VA R+68
- Antelope County, NE R+71
- Osceola County, IA R+57
- Lafayette County, AR R+32
- Quitman County, MS D+44
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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.