02138 is a Democratic stronghold. About 89% of voters here vote Democratic and 11% Republican.
About 56% of adults in 02138 typically vote, below the U.S. average of about 62%. Among adults in 02138, ~50% vote Democratic, ~6% Republican, and ~44% don't vote. The map below shows estimated turnout by block group.
How 02138 compares
Among zip codes within 15 miles, 02138 is the most Democratic-leaning.
02138 runs about 53 points more Democratic than Massachusetts as a whole.
Why 02138 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 02138, not a ranked or complete list of what matters most.
Areas with high college attainment vote Democratic. About 85% of adults in 02138 hold a bachelor's degree, about 56 points above the U.S. average of 28%. Dense areas vote Democratic, and 02138 sits in the top fifth on density (about 97%, above 93% of zip codes). A high never-married share predicts Democratic voting, and about 58% of adults in 02138 have never been married, above 98% of zip codes.
Population density and Democratic lean
Places with high population density tend to lean Democratic; 02138, MA sits in the top tenth nationally on this measure.
Why turnout in 02138 looks the way it does
Renters vote less often than owners. About 63% of households in 02138 rent, about 38 points above the U.S. average of 25%. Strong routine healthcare access lines up with higher turnout, and 02138 sits in the top quarter on routine-care measures. 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.