Northbrook leans heavily Democratic by roughly 32 points: about 66% of voters vote Democratic and 34% Republican.
About 86% of adults in Northbrook typically vote, above the U.S. average of about 62%. Among adults in Northbrook, ~57% vote Democratic, ~29% Republican, and ~14% don't vote. The map below shows estimated turnout by block group.
How Northbrook compares
Among cities within 25 miles, Northbrook leans more Democratic than 129 of 155 neighbors.
Northbrook runs about 21 points more Democratic than Illinois as a whole.
Politics vary noticeably by neighborhood within Northbrook. The northeast side is the most Democratic-leaning (D+39) and the southwest side is the least Democratic-leaning (D+21), a spread of about 18 points.
Why Northbrook 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 Northbrook, not a ranked or complete list of what matters most.
Areas with high college attainment vote Democratic. About 72% of adults in Northbrook hold a bachelor's degree, about 43 points above the U.S. average of 28%. Dense areas vote Democratic, and Northbrook sits in the top fifth on density (about 91%, above 97% of cities).
Population density and Democratic lean
Places with high population density tend to lean Democratic; Northbrook, IL sits in the top tenth nationally on this measure.
Why turnout in Northbrook looks the way it does
Areas with strong routine healthcare access turn out at higher rates. Northbrook 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%. High high-school completion lines up with higher turnout, and about 97% of adults in Northbrook have completed high school, above 88% of cities. Learn more about the findings and methodology on the political spectrum map.
Nearby Cities
- Glenview Nas, IL D+26
- Deerfield, IL D+45
- Glenview, IL D+21
- Northfield, IL D+26
- Prospect Heights, IL D+9
- Riverwoods, IL D+29
- Highland Park, IL D+50
- Glencoe, IL D+47
- Wheeling, IL D+15
- Bannockburn, IL D+26
Cities with Similar Populations
- Starkville, MS D+6
- Paducah, KY R+20
- Sierra Vista, AZ R+18
- New Berlin, WI R+14
- Rockledge, FL R+17
- Hope Mills, NC D+4
- Streamwood, IL D+11
- Upper Darby, PA D+53
- Bartlesville, OK R+35
- Monroe, GA R+33
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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.