Mason City leans heavily Republican by roughly 44 points: about 28% of voters vote Democratic and 72% Republican.
About 74% of adults in Mason City typically vote, above the U.S. average of about 62%. Among adults in Mason City, ~21% vote Democratic, ~53% Republican, and ~26% don't vote. The map below shows estimated turnout by block group.
How Mason City compares
Among cities within 25 miles, Mason City leans more Republican than 12 of 58 neighbors.
Mason City runs about 54 points more Republican than Illinois as a whole. Illinois leans Democratic overall, while Mason City is one of the few Republican-leaning pockets.
Politics vary noticeably by neighborhood within Mason City. The southeast side is the most Republican-leaning (R+53) and the north side is the least Republican-leaning (R+40), a spread of about 13 points.
Why Mason City leans the way it does
This analysis examined 14,881 data points per city to find what predicts political lean and turnout. The items below are a few correlations that stood out for Mason City, not a ranked or complete list of what matters most.
Mason City votes against the grain of Illinois. Illinois leans Democratic overall, while Mason City runs about 54 points more Republican. Dense places usually vote Democratic, but Mason City runs against that pattern.
Population density and Democratic lean
Places with high population density tend to lean Democratic; Mason City, IL sits in the top quarter nationally on this measure.
Why turnout in Mason City looks the way it does
Turnout in Mason City 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 Cities
- Teheran, IL R+58
- Hubly, IL R+57
- Natrona, IL R+58
- New Holland, IL R+58
- San Jose, IL R+57
- Greenview, IL R+51
- Easton, IL R+58
- Middletown, IL R+54
- Sweet Water, IL R+56
- Emden, IL R+57
Cities with Similar Populations
- Electra, TX R+61
- Littlerock, CA R+10
- Owen, WI R+42
- Machias, ME R+27
- Uniontown, AL D+70
- Muenster, TX R+76
- Morristown, IN R+54
- Gaston, NC D+23
- Montour Falls, NY R+27
- Portville, NY R+37
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.