Plymouth County leans slightly Democratic by roughly 10 points: about 55% of voters vote Democratic and 45% Republican.
About 80% of adults in Plymouth County typically vote, above the U.S. average of about 62%. Among adults in Plymouth County, ~44% vote Democratic, ~36% Republican, and ~20% don't vote. The map below shows estimated turnout by block group.
How Plymouth County compares
Among counties within 50 miles, Plymouth County leans more Democratic than 2 of 11 neighbors.
Plymouth County runs about 14 points more Republican than Massachusetts as a whole.
Politics vary noticeably by city within Plymouth County. The northwest side runs the most Democratic (D+26) and the south side runs the most Republican (R+6), a spread of about 33 points.
Why Plymouth 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 Plymouth County, not a ranked or complete list of what matters most.
Dense areas vote Democratic. About 54% of residents in Plymouth County live in densely developed areas, about 18 points above the U.S. average of 36%. High college attainment predicts Democratic voting, and Plymouth County sits in the top quarter (about 42%, above 93% of counties).
Preventive-care access and voter turnout
Places with strong routine preventive-care access tend to turn out at a higher rate; Plymouth County, MA sits in the top tenth nationally on this measure. Dental visits do not drive turnout; the rate reflects income, insurance, and healthcare access, which line up with who votes.
Why turnout in Plymouth County looks the way it does
Areas with strong routine healthcare access turn out at higher rates. Plymouth 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 71%, about 11 points above the U.S. average of 60%. Learn more about the findings and methodology on the political spectrum map.
Nearby Counties
- Norfolk County, MA D+30
- Bristol County, MA Even
- Suffolk County, MA D+53
- Bristol County, RI D+17
- Providence County, RI D+20
- Barnstable County, MA D+20
- Middlesex County, MA D+37
- Newport County, RI D+23
- Kent County, RI D+5
- Essex County, MA D+18
Counties with Similar Populations
- Chester County, PA D+14
- Greenville County, SC R+14
- Montgomery County, OH D+6
- Passaic County, NJ D+4
- Sedgwick County, KS R+7
- Camden County, NJ D+30
- Spokane County, WA R+3
- Summit County, OH D+10
- Guilford County, NC D+30
- Adams County, CO D+11
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.