South Barrington, IL Political Map | Democrat & Republican Areas in South Barrington

By the BestNeighborhood data science team. Last updated May 2026.

South Barrington leans slightly Republican by roughly 8 points: about 46% of voters vote Democratic and 54% Republican.

 

About 76% of adults in South Barrington typically vote, above the U.S. average of about 62%. Among adults in South Barrington, ~35% vote Democratic, ~41% Republican, and ~24% don't vote. The map below shows estimated turnout by block group.

How South Barrington compares

Among cities within 25 miles, South Barrington leans more Republican than 152 of 186 neighbors.

South Barrington runs about 18 points more Republican than Illinois as a whole. Illinois leans Democratic overall, while South Barrington is one of the few Republican-leaning pockets.

Politics vary noticeably by neighborhood within South Barrington. The northeast side runs the most Democratic (Even) and the north side runs the most Republican (R+13), a spread of about 14 points.

Why South Barrington 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 South Barrington, not a ranked or complete list of what matters most.

South Barrington votes Republican even though it is densely developed (about 66%, far above the Illinois average of 33%). State and regional patterns outweigh the Democratic lean that density usually predicts here. A high family-household share predicts Republican voting, and about 91% of households in South Barrington are family households, in the top fraction of cities. South Barrington runs against the grain of Illinois, a Republican-leaning pocket in a Democratic-leaning state.

Food insecurity and voter turnout

Places with low food insecurity tend to turn out at a higher rate; South Barrington, IL sits in the bottom tenth nationally on this measure. Food insecurity does not directly drive turnout; it reflects economic hardship, which lines up with lower voting.

Why turnout in South Barrington looks the way it does

Areas with strong routine healthcare access turn out at higher rates. South Barrington 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 75%, about 15 points above the U.S. average of 60%. Homeowners vote more often than renters, and about 98% of households in South Barrington own their home, compared to around 78% in nearby cities. High high-school completion lines up with higher turnout, and about 97% of adults in South Barrington have completed high school, above 88% of cities. Learn more about the findings and methodology on the political spectrum map.

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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.