01104 leans heavily Democratic by roughly 30 points: about 65% of voters vote Democratic and 35% Republican.
About 51% of adults in 01104 typically vote, below the U.S. average of about 62%. Among adults in 01104, ~33% vote Democratic, ~18% Republican, and ~49% don't vote. The map below shows estimated turnout by block group.
How 01104 compares
Among zip codes within 15 miles, 01104 leans more Democratic than 29 of 41 neighbors.
01104 runs about 6 points more Democratic than Massachusetts as a whole.
Politics vary noticeably by block within 01104. The southwest side is the most Democratic-leaning (D+42) and the northeast side is the least Democratic-leaning (D+15), a spread of about 27 points.
Why 01104 leans the way it does
This analysis examined 14,881 data points per zip code to find what predicts political lean and turnout. The items below are a few correlations that stood out for 01104, not a ranked or complete list of what matters most.
Dense areas vote Democratic. About 96% of residents in 01104 live in densely developed areas, about 60 points above the U.S. average of 36%. A high never-married share predicts Democratic voting, and about 53% of adults in 01104 have never been married, above 96% of zip codes.
Population density and Democratic lean
Places with high population density tend to lean Democratic; 01104, MA sits in the top tenth nationally on this measure.
Why turnout in 01104 looks the way it does
Areas with limited routine healthcare access turn out at lower rates. 01104 is in the bottom quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. Renters vote less often than owners, and about 49% of households in 01104 rent, about 24 points above the U.S. average of 25%. High food insecurity lines up with lower turnout, and about 33% of adults in 01104 report food insecurity, above 96% of zip codes. Learn more about the findings and methodology on the political spectrum map.
Nearby Zip Codes
Zip Codes with Similar Populations
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.