Osterville leans Democratic by roughly 22 points: about 61% of voters vote Democratic and 39% Republican.
About 89% of adults in Osterville typically vote, above the U.S. average of about 62%. Among adults in Osterville, ~54% vote Democratic, ~35% Republican, and ~11% don't vote. The map below shows estimated turnout by block group.
How Osterville compares
Among cities within 25 miles, Osterville leans more Democratic than 49 of 70 neighbors.
Politically, Osterville sits close to the rest of Massachusetts.
Politics vary noticeably by neighborhood within Osterville. The east side is the most Democratic-leaning (D+27) and the southwest side is the least Democratic-leaning (D+15), a spread of about 12 points.
Why Osterville 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 Osterville, not a ranked or complete list of what matters most.
Areas with high college attainment vote Democratic. About 60% of adults in Osterville hold a bachelor's degree, about 31 points above the U.S. average of 28%. Dense areas vote Democratic, and Osterville sits in the top fifth on density (about 68%, above 92% of cities).
Population density and Democratic lean
Places with high population density tend to lean Democratic; Osterville, MA sits in the top quarter nationally on this measure.
Why turnout in Osterville looks the way it does
Areas with strong routine healthcare access turn out at higher rates. Osterville 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 78%, about 18 points above the U.S. average of 60%. Homeowners vote more often than renters, and about 94% of households in Osterville own their home, about 19 points above the U.S. average of 75%. High high-school completion lines up with higher turnout, and about 98% of adults in Osterville have completed high school, above 95% of cities. Learn more about the findings and methodology on the political spectrum map.
Nearby Cities
- Centerville, MA D+11
- Marstons Mills, MA D+9
- Cotuit, MA D+20
- Hyannis Port, MA D+12
- West Barnstable, MA D+9
- Barnstable Town, MA D+17
- Mashpee, MA D+13
- Barnstable, MA D+16
- East Sandwich, MA D+8
- Sandwich, MA D+13
Cities with Similar Populations
- Columbus, KS R+52
- New Glarus, WI Even
- Holloman AFB, NM R+12
- Ruffin, NC R+49
- Henning, TN R+33
- Biscoe, NC R+23
- Pennington Gap, VA R+58
- Roebling, NJ D+5
- Grantsburg, WI R+36
- Springville, IN R+57
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Sources and methodology
Precinct-level voting records used to fit the model come from Massachusetts Secretary of the Commonwealth, 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.