Mason County leans heavily Republican by roughly 46 points: about 27% of voters vote Democratic and 73% Republican.
About 78% of adults in Mason County typically vote, above the U.S. average of about 62%. Among adults in Mason County, ~21% vote Democratic, ~57% Republican, and ~22% don't vote. The map below shows estimated turnout by block group.
How Mason County compares
Among counties within 50 miles, Mason County is the most Republican-leaning.
Mason County runs about 57 points more Republican than Illinois as a whole. Illinois leans Democratic overall, while Mason County is one of the few Republican-leaning pockets.
Politics vary noticeably by city within Mason County. The south side is the most Republican-leaning (R+57) and the northwest side is the least Republican-leaning (R+39), a spread of about 19 points.
Why Mason 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 Mason County, not a ranked or complete list of what matters most.
Areas with a high white share and below-average college attainment vote Republican. In Mason County, about 94% of residents are non-Hispanic white, about 22 points above the U.S. average of 72%; about 16% of adults hold a bachelor's degree, about 10 points below the Illinois average of 27%. Car-dependent areas vote Republican, and about 82% of residents in Mason County drive to work alone, above 81% of counties. Mason 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; Mason County, IL sits below the national average on this measure. A walkable street grid does not change how people vote; it mostly reflects how urban a place is.
Why turnout in Mason County looks the way it does
Homeowners vote more often than renters. About 82% of households in Mason County own their home, about 7 points above the U.S. average of 75%. Learn more about the findings and methodology on the political spectrum map.
Nearby Counties
- Fulton County, IL R+31
- Menard County, IL R+41
- Tazewell County, IL R+29
- Logan County, IL R+41
- Cass County, IL R+31
- Peoria County, IL D+14
- Schuyler County, IL R+44
- Sangamon County, IL Even
- McDonough County, IL R+11
- Morgan County, IL R+25
Counties with Similar Populations
- Lewis County, KY R+66
- Kodiak Island Borough, AK R+16
- Big Horn County, MT Even
- Cass County, IA R+41
- Lamb County, TX R+57
- Powell County, KY R+60
- Cass County, IL R+31
- Webster County, KY R+58
- Perquimans County, NC R+34
- Shoshone County, ID R+43
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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.