Whiteside County leans Republican by roughly 20 points: about 40% of voters vote Democratic and 60% Republican.
About 73% of adults in Whiteside County typically vote, above the U.S. average of about 62%. Among adults in Whiteside County, ~29% vote Democratic, ~44% Republican, and ~27% don't vote. The map below shows estimated turnout by block group.
How Whiteside County compares
Among counties within 50 miles, Whiteside County leans more Republican than 3 of 12 neighbors.
Whiteside County runs about 31 points more Republican than Illinois as a whole. Illinois leans Democratic overall, while Whiteside County is one of the few Republican-leaning pockets.
Politics vary noticeably by city within Whiteside County. The southwest side is the most Republican-leaning (R+46) and the east side is the least Republican-leaning (R+3), a spread of about 43 points.
Why Whiteside County leans the way it does
This analysis examined 14,881 data points per county to find what predicts political lean and turnout. The items below are a few correlations that stood out for Whiteside County, not a ranked or complete list of what matters most.
Whiteside County votes Republican even though it is densely developed (about 48%, well above the Illinois average of 33%). State and regional patterns outweigh the Democratic lean that density usually predicts here. Whiteside County 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; Whiteside County, IL sits in the top quarter nationally on this measure.
Why turnout in Whiteside County looks the way it does
Turnout in Whiteside County 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 Counties
- Carroll County, IL R+34
- Lee County, IL R+21
- Clinton County, IA R+21
- Henry County, IL R+24
- Ogle County, IL R+28
- Bureau County, IL R+27
- Stephenson County, IL R+14
- Rock Island County, IL D+12
- Scott County, IA D+5
- Jackson County, IA R+35
Counties with Similar Populations
- Campbell County, VA R+37
- Eagle County, CO D+14
- La Plata County, CO D+13
- Tuolumne County, CA R+18
- Lafayette County, MS R+16
- Hancock County, ME D+5
- Taney County, MO R+50
- Pearl River County, MS R+60
- Marion County, WV R+37
- Cherokee County, SC R+42
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.