Harrisburg leans heavily Republican by roughly 44 points: about 28% of voters vote Democratic and 72% Republican.
About 72% of adults in Harrisburg typically vote, above the U.S. average of about 62%. Among adults in Harrisburg, ~20% vote Democratic, ~52% Republican, and ~28% don't vote. The map below shows estimated turnout by block group.
How Harrisburg compares
Among cities within 25 miles, Harrisburg leans more Republican than 2 of 75 neighbors.
Harrisburg runs about 54 points more Republican than Illinois as a whole. Illinois leans Democratic overall, while Harrisburg is one of the few Republican-leaning pockets.
Politics vary noticeably by neighborhood within Harrisburg. The northwest side is the most Republican-leaning (R+53) and the east side is the least Republican-leaning (R+36), a spread of about 17 points.
Why Harrisburg 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 Harrisburg, not a ranked or complete list of what matters most.
Car-dependent areas vote Republican. About 88% of residents in Harrisburg drive to work alone, about 14 points above the U.S. average of 74%. Harrisburg runs against the grain of Illinois, a Republican-leaning pocket in a Democratic-leaning state.
Population density and Democratic lean
Places with high population density tend to lean Democratic; Harrisburg, IL sits in the top quarter nationally on this measure.
Why turnout in Harrisburg looks the way it does
Turnout in Harrisburg sits close to the national pattern. Routine healthcare access, homeownership, education, and food security all land near their national averages here. Learn more about the findings and methodology on the political spectrum map.
Nearby Cities
- Garden Heights, IL R+56
- Pankeyville, IL R+61
- Ledford, IL R+59
- Muddy, IL R+56
- Carrier Mills, IL R+52
- Wasson, IL R+62
- Mitchellsville, IL R+64
- Harco, IL R+64
- Raleigh, IL R+63
- Somerset, IL R+61
Cities with Similar Populations
- Triangle, VA D+43
- Parsons, KS R+25
- Belle Vernon, PA R+30
- Coarsegold, CA R+29
- Cedar Hills, UT R+43
- South Haven, MI Even
- Red Bank, SC R+43
- Walkertown, NC R+24
- Kempner, TX R+52
- Pocahontas, AR R+59
All Local Stats
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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.