McDonough County leans slightly Republican by roughly 12 points: about 44% of voters vote Democratic and 56% Republican.
About 66% of adults in McDonough County typically vote, near the U.S. average of about 62%. Among adults in McDonough County, ~29% vote Democratic, ~37% Republican, and ~34% don't vote. The map below shows estimated turnout by block group.
How McDonough County compares
Among counties within 50 miles, McDonough County leans more Republican than 2 of 11 neighbors.
McDonough County runs about 22 points more Republican than Illinois as a whole. Illinois leans Democratic overall, while McDonough County is one of the few Republican-leaning pockets.
Politics vary noticeably by city within McDonough County. The east side is the most Republican-leaning (R+49) and the south side is the least Republican-leaning (R+20), a spread of about 29 points.
Why McDonough 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 McDonough County, not a ranked or complete list of what matters most.
McDonough County votes against the grain of Illinois. Illinois leans Democratic overall, while McDonough County runs about 22 points more Republican.
High-school completion, uninsured rate, and voter turnout
Places that combine high-school-completion-heavy adults and a low uninsured rate tend to turn out at a higher rate, as McDonough County, IL does.
Why turnout in McDonough County looks the way it does
Areas with high high-school completion turn out at higher rates. About 95% of adults in McDonough County have completed high school, above 89% of counties. Learn more about the findings and methodology on the political spectrum map.
Nearby Counties
- Schuyler County, IL R+44
- Hancock County, IL R+45
- Henderson County, IL R+41
- Warren County, IL R+22
- Fulton County, IL R+31
- Brown County, IL R+39
- Des Moines County, IA R+8
- Knox County, IL R+9
- Cass County, IL R+31
- Lee County, IA R+27
Counties with Similar Populations
- Union County, SC R+28
- Fluvanna County, VA R+16
- San Miguel County, NM D+24
- West Baton Rouge Parish, LA R+9
- Cibola County, NM D+10
- White County, TN R+66
- Pike County, OH R+58
- Tillamook County, OR R+9
- Orleans County, VT R+17
- Iroquois County, IL R+48
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.