20817 is a Democratic stronghold. About 80% of voters here vote Democratic and 20% Republican.
About 86% of adults in 20817 typically vote, above the U.S. average of about 62%. Among adults in 20817, ~69% vote Democratic, ~17% Republican, and ~14% don't vote. The map below shows estimated turnout by block group.
How 20817 compares
Among zip codes within 15 miles, 20817 leans more Democratic than 70 of 126 neighbors.
20817 runs about 31 points more Democratic than Maryland as a whole.
Politics vary noticeably by block within 20817. The east side is the most Democratic-leaning (D+68) and the west side is the least Democratic-leaning (D+50), a spread of about 18 points.
Why 20817 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 20817, not a ranked or complete list of what matters most.
Areas with high college attainment vote Democratic. About 86% of adults in 20817 hold a bachelor's degree, about 57 points above the U.S. average of 28%. Dense areas vote Democratic, and 20817 sits in the top fifth on density (about 92%, above 89% of zip codes).
Walkability and Democratic lean
Places with a highly walkable street grid tend to lean Democratic; 20817, MD sits in the top quarter 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 20817 looks the way it does
Areas with strong routine healthcare access turn out at higher rates. 20817 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%. High high-school completion lines up with higher turnout, and about 98% of adults in 20817 have completed high school, above 95% 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 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.