Island Lake leans slightly Republican by roughly 8 points: about 46% of voters vote Democratic and 54% Republican.
About 77% of adults in Island Lake typically vote, above the U.S. average of about 62%. Among adults in Island Lake, ~35% vote Democratic, ~42% Republican, and ~23% don't vote. The map below shows estimated turnout by block group.
How Island Lake compares
Among cities within 25 miles, Island Lake leans more Republican than 98 of 145 neighbors.
Island Lake runs about 19 points more Republican than Illinois as a whole. Illinois leans Democratic overall, while Island Lake is one of the few Republican-leaning pockets.
Politics vary noticeably by neighborhood within Island Lake. The east side is the most split-leaning (R+16) and the west side is the least split-leaning (Even), a spread of about 15 points.
Why Island Lake 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 Island Lake, not a ranked or complete list of what matters most.
Island Lake votes Republican even though it is densely developed (about 63%, far above the Illinois average of 33%). State and regional patterns outweigh the Democratic lean that density usually predicts here. Island Lake 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; Island Lake, IL sits in the top tenth nationally on this measure.
Why turnout in Island Lake looks the way it does
Turnout in Island Lake 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
- Holiday Hills, IL R+13
- Port Barrington, IL R+6
- Oakwood Hills, IL R+10
- Wauconda, IL Even
- Prairie Grove, IL R+10
- Tower Lakes, IL D+7
- Lakemoor, IL R+12
- Volo, IL Even
- Cary, IL Even
- Lake Barrington, IL D+6
Cities with Similar Populations
- Montecito, CA D+40
- Kaplan, LA R+59
- Northwest Harborcreek, PA R+5
- Caseyville, IL R+8
- Riviera Beach, MD R+20
- Bridgeville, DE R+16
- Halfway, MD R+24
- Milan, IL R+9
- Needville, TX R+50
- Breckenridge, CO D+24
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.