20878 leans heavily Democratic by roughly 48 points: about 74% of voters vote Democratic and 26% Republican.
About 70% of adults in 20878 typically vote, above the U.S. average of about 62%. Among adults in 20878, ~52% vote Democratic, ~18% Republican, and ~30% don't vote. The map below shows estimated turnout by block group.
How 20878 compares
Among zip codes within 15 miles, 20878 leans more Democratic than 35 of 58 neighbors.
20878 runs about 18 points more Democratic than Maryland as a whole.
Politics vary noticeably by block within 20878. The north side is the most Democratic-leaning (D+51) and the southwest side is the least Democratic-leaning (D+41), a spread of about 10 points.
Why 20878 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 20878, not a ranked or complete list of what matters most.
Areas with high college attainment vote Democratic. About 70% of adults in 20878 hold a bachelor's degree, about 41 points above the U.S. average of 28%. Dense areas vote Democratic, and 20878 sits in the top fifth on density (about 82%, above 84% of zip codes).
Walkability and Democratic lean
Places with a highly walkable street grid tend to lean Democratic; 20878, MD sits in the top tenth nationally on this measure. A walkable street grid does not change how people vote; it mostly reflects how urban a place is.
Why turnout in 20878 looks the way it does
Areas with strong routine healthcare access turn out at higher rates. 20878 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 72%, about 12 points above the U.S. average of 60%. 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 Maryland 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.