LaSalle County leans Republican by roughly 20 points: about 40% of voters vote Democratic and 60% Republican.
About 73% of adults in LaSalle County typically vote, above the U.S. average of about 62%. Among adults in LaSalle County, ~29% vote Democratic, ~44% Republican, and ~27% don't vote. The map below shows estimated turnout by block group.
How LaSalle County compares
Among counties within 50 miles, LaSalle County leans more Republican than 4 of 12 neighbors.
LaSalle County runs about 31 points more Republican than Illinois as a whole. Illinois leans Democratic overall, while LaSalle County is one of the few Republican-leaning pockets.
Politics vary noticeably by city within LaSalle County. The northeast side is the most Republican-leaning (R+31) and the west side is the least Republican-leaning (R+9), a spread of about 22 points.
Why LaSalle 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 LaSalle County, not a ranked or complete list of what matters most.
Car-dependent areas vote Republican. About 84% of residents in LaSalle County drive to work alone, about 10 points above the U.S. average of 74%. LaSalle 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; LaSalle County, IL sits in the top quarter nationally on this measure.
Why turnout in LaSalle County looks the way it does
Turnout in LaSalle 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
- Putnam County, IL R+28
- Bureau County, IL R+27
- Grundy County, IL R+26
- Marshall County, IL R+37
- Kendall County, IL Even
- Livingston County, IL R+38
- DeKalb County, IL D+3
- Lee County, IL R+21
- Woodford County, IL R+40
- Will County, IL D+6
Counties with Similar Populations
- Warren County, NJ R+16
- Terrebonne Parish, LA R+42
- Hanover County, VA R+21
- Pennington County, SD R+28
- Eaton County, MI R+8
- Madison County, MS R+5
- Bartow County, GA R+46
- Miami County, OH R+42
- Mercer County, PA R+27
- Bradley County, TN R+48
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.