Algonquin is a true toss-up. About 50% of voters here vote Democratic and 50% Republican.
About 83% of adults in Algonquin typically vote, above the U.S. average of about 62%. Among adults in Algonquin, ~41% vote Democratic, ~42% Republican, and ~17% don't vote. The map below shows estimated turnout by block group.
How Algonquin compares
Among cities within 25 miles, Algonquin sits roughly in the middle of the political spectrum, with 82 neighbors leaning further in the place's direction and 58 leaning the other way.
Algonquin runs about 11 points more Republican than Illinois as a whole.
Why Algonquin leans the way it does
Density, race composition, education, and family structure all sit close to their national averages in Algonquin. The lean here lands roughly where demographic data alone would predict.
Population density and Democratic lean
Places with high population density tend to lean Democratic; Algonquin, IL sits in the top tenth nationally on this measure.
Why turnout in Algonquin looks the way it does
Areas with strong routine healthcare access turn out at higher rates. Algonquin is in the top quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. The dental-visit rate here is about 68%, about 8 points above the U.S. average of 60%. High high-school completion lines up with higher turnout, and about 96% of adults in Algonquin have completed high school, above 81% of cities. Learn more about the findings and methodology on the political spectrum map.
Nearby Cities
- Carpentersville, IL D+17
- Lake in the Hills, IL Even
- Dundee, IL Even
- Trout Valley, IL Even
- West Dundee, IL D+10
- East Dundee, IL D+6
- Sleepy Hollow, IL D+5
- Crystal Lake, IL D+3
- Barrington Hills, IL Even
- Cary, IL Even
Cities with Similar Populations
- Aberdeen, SD R+31
- Wisconsin Rapids, WI R+18
- Oakdale, CA R+28
- Ozark, MO R+47
- Locust Grove, GA D+2
- Lancaster, NY R+13
- Elkhorn, NE R+17
- Palm City, FL R+33
- Henderson, NC D+28
- O'Fallon, IL D+8
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.