62421 is a Republican stronghold. About 17% of voters here vote Democratic and 83% Republican.
About 88% of adults in 62421 typically vote, above the U.S. average of about 62%. Among adults in 62421, ~15% vote Democratic, ~73% Republican, and ~12% don't vote. The map below shows estimated turnout by block group.
How 62421 compares
Among zip codes within 15 miles, 62421 leans more Republican than 4 of 10 neighbors.
62421 runs about 77 points more Republican than Illinois as a whole. Illinois leans Democratic overall, while 62421 is one of the few Republican-leaning pockets.
Why 62421 leans the way it does
This analysis examined 14,881 data points per zip code to find what predicts political lean and turnout. The items below are a few correlations that stood out for 62421, not a ranked or complete list of what matters most.
62421 votes against the grain of Illinois. Illinois leans Democratic overall, while 62421 runs about 77 points more Republican.
Walkability and Republican lean
Places with a low walkability score tend to lean Republican; 62421, IL sits in the bottom tenth nationally on this measure. A walkable street grid does not change how people vote; it mostly reflects how urban a place is.
Why turnout in 62421 looks the way it does
Homeowners vote more often than renters. About 94% of households in 62421 own their home, about 15 points above the Illinois average of 80%. Learn more about the findings and methodology on the political spectrum map.
Nearby Zip Codes
Zip Codes with Similar Populations
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.