Spring Valley leans slightly Republican by roughly 8 points: about 46% of voters vote Democratic and 54% Republican.
About 76% of adults in Spring Valley typically vote, above the U.S. average of about 62%. Among adults in Spring Valley, ~35% vote Democratic, ~41% Republican, and ~24% don't vote. The map below shows estimated turnout by block group.
How Spring Valley compares
Among cities within 25 miles, Spring Valley leans more Republican than 1 of 68 neighbors.
Spring Valley runs about 20 points more Republican than Illinois as a whole. Illinois leans Democratic overall, while Spring Valley is one of the few Republican-leaning pockets.
Why Spring Valley 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 Spring Valley, not a ranked or complete list of what matters most.
Spring Valley votes Republican even though it is densely developed (about 36%, above 83% of cities). State and regional patterns outweigh the Democratic lean that density usually predicts here. Spring Valley 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; Spring Valley, IL sits in the top quarter nationally on this measure.
Why turnout in Spring Valley looks the way it does
Turnout in Spring Valley 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
- Dalzell, IL R+22
- Ladd, IL R+24
- Peru, IL R+10
- Seatonville, IL R+28
- Granville, IL R+19
- Mark, IL R+29
- DePue, IL D+2
- Standard, IL R+32
- Hollowayville, IL R+33
- Lasalle, IL R+9
Cities with Similar Populations
- Midfield, AL D+85
- Vinton, IA R+24
- Perryville, MD R+22
- Bush, LA R+70
- Wesson, MS R+47
- East Sandwich, MA D+8
- Alexander, NC R+26
- Cumberland, IN R+6
- Rainier, OR R+25
- Bailey, CO R+17
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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.