Tompkins County leans heavily Democratic by roughly 50 points: about 75% of voters vote Democratic and 25% Republican.
About 63% of adults in Tompkins County typically vote, near the U.S. average of about 62%. Among adults in Tompkins County, ~47% vote Democratic, ~16% Republican, and ~37% don't vote. The map below shows estimated turnout by block group.
How Tompkins County compares
Among counties within 50 miles, Tompkins County is the most Democratic-leaning.
Tompkins County runs about 37 points more Democratic than New York as a whole.
Politics vary noticeably by city within Tompkins County. The south side is the most Democratic-leaning (D+67) and the northeast side is the least Democratic-leaning (D+2), a spread of about 65 points.
Why Tompkins 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 Tompkins County, not a ranked or complete list of what matters most.
Areas with high college attainment vote Democratic. About 59% of adults in Tompkins County hold a bachelor's degree, about 31 points above the U.S. average of 28%. A high never-married share predicts Democratic voting, and about 47% of adults in Tompkins County have never been married, above 98% of counties.
Population density and Democratic lean
Places with high population density tend to lean Democratic; Tompkins County, NY sits in the top tenth nationally on this measure.
Why turnout in Tompkins County looks the way it does
Areas with strong routine healthcare access turn out at higher rates. Tompkins 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 64%, above 75% of counties. High high-school completion lines up with higher turnout, and about 95% of adults in Tompkins County have completed high school, above 91% of counties. Learn more about the findings and methodology on the political spectrum map.
Nearby Counties
- Cortland County, NY R+17
- Schuyler County, NY R+23
- Tioga County, NY R+27
- Chemung County, NY R+14
- Seneca County, NY R+18
- Yates County, NY R+28
- Cayuga County, NY R+17
- Broome County, NY D+3
- Bradford County, PA R+49
- Onondaga County, NY D+21
Counties with Similar Populations
- Eau Claire County, WI D+10
- Monongalia County, WV D+4
- Sumter County, SC D+9
- Woodbury County, IA R+9
- Vigo County, IN R+12
- Walworth County, WI R+17
- Navajo County, AZ R+3
- Platte County, MO R+5
- Franklin County, MO R+48
- Carver County, MN R+8
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.