62703 leans heavily Democratic by roughly 32 points: about 66% of voters vote Democratic and 34% Republican.
About 58% of adults in 62703 typically vote, near the U.S. average of about 62%. Among adults in 62703, ~38% vote Democratic, ~20% Republican, and ~42% don't vote. The map below shows estimated turnout by block group.
How 62703 compares
Among zip codes within 15 miles, 62703 leans more Democratic than 22 of 23 neighbors.
62703 runs about 21 points more Democratic than Illinois as a whole.
Politics vary noticeably by block within 62703. The north side runs the most Democratic (D+68) and the southwest side runs the most Republican (R+5), a spread of about 73 points.
Why 62703 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 62703, not a ranked or complete list of what matters most.
Dense areas vote Democratic. About 88% of residents in 62703 live in densely developed areas, about 51 points above the U.S. average of 36%. A high never-married share predicts Democratic voting, and about 47% of adults in 62703 have never been married, above 93% of zip codes.
Paved land cover and Democratic lean
Places with extensive paved surfaces tend to lean Democratic; 62703, IL sits in the top quarter 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 62703 looks the way it does
Areas with high food insecurity turn out at lower rates. About 29% of adults in 62703 report food insecurity, about 13 points above the U.S. average of 16%. Limited routine healthcare access lines up with lower turnout, and 62703 sits in the bottom quarter on routine-care measures. Renters vote less often than owners, and about 41% of households in 62703 rent, about 16 points above the U.S. average of 25%. 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.