Onondaga County, NY Political Map | Democrat & Republican Areas in Onondaga County

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

Onondaga County leans Democratic by roughly 20 points: about 60% of voters vote Democratic and 40% Republican.

 

About 70% of adults in Onondaga County typically vote, above the U.S. average of about 62%. Among adults in Onondaga County, ~42% vote Democratic, ~28% Republican, and ~30% don't vote. The map below shows estimated turnout by block group.

How Onondaga County compares

Among counties within 50 miles, Onondaga County leans more Democratic than 7 of 8 neighbors.

Onondaga County runs about 8 points more Democratic than New York as a whole.

Politics vary noticeably by city within Onondaga County. The south side runs the most Democratic (D+48) and the northeast side runs the most Republican (R+4), a spread of about 52 points.

Why Onondaga County leans the way it does

This analysis examined 14,881 data points per county to find what predicts political lean and turnout. The items below are a few correlations that stood out for Onondaga County, not a ranked or complete list of what matters most.

Dense areas vote Democratic. About 74% of residents in Onondaga County live in densely developed areas, about 38 points above the U.S. average of 36%. High college attainment predicts Democratic voting, and Onondaga County sits in the top quarter (about 40%, above 91% of counties). A high never-married share predicts Democratic voting, and about 37% of adults in Onondaga County have never been married, above 89% of counties.

Paved land cover and Democratic lean

Places with extensive paved surfaces tend to lean Democratic; Onondaga County, NY sits in the top tenth nationally on this measure. Paved ground does not change how people vote; it mostly reflects how urban and built-up a place is.

Why turnout in Onondaga County looks the way it does

Areas with strong routine healthcare access turn out at higher rates. Onondaga County 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 65%, above 78% of counties. Learn more about the findings and methodology on the political spectrum map.

Sources and methodology

Precinct-level voting records used to fit the model come from New York 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.