Somonauk leans Republican by roughly 26 points: about 37% of voters vote Democratic and 63% Republican.
About 86% of adults in Somonauk typically vote, above the U.S. average of about 62%. Among adults in Somonauk, ~32% vote Democratic, ~54% Republican, and ~14% don't vote. The map below shows estimated turnout by block group.
How Somonauk compares
Among cities within 25 miles, Somonauk leans more Republican than 29 of 66 neighbors.
Somonauk runs about 38 points more Republican than Illinois as a whole. Illinois leans Democratic overall, while Somonauk is one of the few Republican-leaning pockets.
Politics vary noticeably by neighborhood within Somonauk. The northeast side is the most Republican-leaning (R+35) and the west side is the least Republican-leaning (R+20), a spread of about 16 points.
Why Somonauk 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 Somonauk, not a ranked or complete list of what matters most.
Somonauk votes against the grain of Illinois. Illinois leans Democratic overall, while Somonauk runs about 38 points more Republican. Dense places usually vote Democratic, but Somonauk runs against that pattern.
Preventive-care access and voter turnout
Places with strong routine preventive-care access tend to turn out at a higher rate; Somonauk, IL sits above the national average 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 Somonauk looks the way it does
Areas with high high-school completion turn out at higher rates. About 97% of adults in Somonauk have completed high school, about 5 points above the Illinois average of 92%. Learn more about the findings and methodology on the political spectrum map.
Nearby Cities
- Sandwich, IL R+20
- Millington, IL R+38
- Leland, IL R+41
- Millhurst, IL R+34
- Millbrook, IL R+43
- Sheridan, IL R+34
- Plano, IL R+3
- Newark, IL R+38
- Hinckley, IL R+23
- Serena, IL R+34
Cities with Similar Populations
- Cedar Bluff, VA R+68
- Weimar, TX R+48
- Lineville, AL R+50
- St. Charles, MN R+30
- Reidland, KY R+45
- Fort Defiance, AZ D+59
- Chandler, OK R+53
- Old Westbury, NY Even
- Putney, VT D+39
- Moose Lake, MN R+13
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.