21817 leans slightly Republican by roughly 12 points: about 44% of voters vote Democratic and 56% Republican.
About 79% of adults in 21817 typically vote, above the U.S. average of about 62%. Among adults in 21817, ~35% vote Democratic, ~45% Republican, and ~20% don't vote. The map below shows estimated turnout by block group.
How 21817 compares
Among zip codes within 15 miles, 21817 leans more Republican than 1 of 11 neighbors.
21817 runs about 40 points more Republican than Maryland as a whole. Maryland leans Democratic overall, while 21817 is one of the few Republican-leaning pockets.
Politics vary noticeably by block within 21817. The south side runs the most Democratic (D+28) and the northeast side runs the most Republican (R+42), a spread of about 70 points.
Why 21817 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 21817, not a ranked or complete list of what matters most.
21817 votes against the grain of Maryland. Maryland leans Democratic overall, while 21817 runs about 40 points more Republican.
Housing overcrowding and voter turnout
Places with low overcrowding tend to turn out at a higher rate; 21817, MD sits in the bottom quarter nationally on this measure.
Why turnout in 21817 looks the way it does
Turnout in 21817 sits close to the national pattern. Routine healthcare access, homeownership, education, and food security all land near their national averages here. 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.