Rio leans heavily Republican by roughly 40 points: about 30% of voters vote Democratic and 70% Republican.
About 93% of adults in Rio typically vote, above the U.S. average of about 62%. Among adults in Rio, ~28% vote Democratic, ~65% Republican, and ~7% don't vote. The map below shows estimated turnout by block group.
How Rio compares
Among cities within 25 miles, Rio leans more Republican than 42 of 58 neighbors.
Rio runs about 50 points more Republican than Illinois as a whole. Illinois leans Democratic overall, while Rio is one of the few Republican-leaning pockets.
Why Rio 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 Rio, not a ranked or complete list of what matters most.
Rio votes against the grain of Illinois. Illinois leans Democratic overall, while Rio runs about 50 points more Republican. A high family-household share predicts Republican voting, and about 83% of households in Rio are family households, above 94% of cities.
Preventive-care access and voter turnout
Places with strong routine preventive-care access tend to turn out at a higher rate; Rio, IL sits in the top quarter nationally on this measure. Dental visits do not drive turnout; the rate reflects income, insurance, and healthcare access, which line up with who votes.
Why turnout in Rio looks the way it does
Areas with high high-school completion turn out at higher rates. About 96% of adults in Rio have completed high school, about 6 points above the U.S. average of 90%. Learn more about the findings and methodology on the political spectrum map.
Nearby Cities
- Henderson Grove, IL R+32
- North Henderson, IL R+31
- Henderson, IL R+34
- Alpha, IL R+34
- Shanghai City, IL R+42
- Wataga, IL R+30
- Woodhull, IL R+31
- New Windsor, IL R+31
- Windsor Mercer County, IL R+31
- Oneida, IL R+37
Cities with Similar Populations
- Moran, MI R+6
- Berino, NM R+4
- Fargo, NY R+53
- Germany, GA R+56
- Laurelhill, MS R+47
- Ephesus, GA R+79
- Rassat, MN R+45
- Pembina, ND R+57
- Laud, IN R+54
- Sheridan, NY R+34
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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.