61820 is a Democratic stronghold. About 79% of voters here vote Democratic and 21% Republican.
About 50% of adults in 61820 typically vote, below the U.S. average of about 62%. Among adults in 61820, ~39% vote Democratic, ~11% Republican, and ~50% don't vote. The map below shows estimated turnout by block group.
How 61820 compares
Among zip codes within 15 miles, 61820 leans more Democratic than 18 of 19 neighbors.
61820 runs about 46 points more Democratic than Illinois as a whole.
Politics vary noticeably by block within 61820. The west side is the most Democratic-leaning (D+69) and the north side is the least Democratic-leaning (D+51), a spread of about 18 points.
Why 61820 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 61820, not a ranked or complete list of what matters most.
Dense areas vote Democratic. More than 99% of residents in 61820 live in densely developed areas, about 63 points above the U.S. average of 36%. High college attainment predicts Democratic voting, and 61820 sits in the top quarter (about 56%, above 92% of zip codes). A high never-married share predicts Democratic voting, and about 78% of adults in 61820 have never been married, in the top fraction of zip codes.
Paved land cover and Democratic lean
Places with extensive paved surfaces tend to lean Democratic; 61820, IL sits in the top tenth nationally on this measure. Paved ground does not change how people vote; it mostly reflects how urban and built-up a place is.
Why turnout in 61820 looks the way it does
Renters vote less often than owners. About 84% of households in 61820 rent, about 59 points above the U.S. average of 25%. High food insecurity lines up with lower turnout, and about 30% of adults in 61820 report food insecurity, above 94% of zip codes. High-crime urban areas turn out at lower rates, and 61820 sits in the top 15% on a violent-crime measure. 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.