21804 leans slightly Democratic by roughly 12 points: about 56% of voters vote Democratic and 44% Republican.
About 68% of adults in 21804 typically vote, above the U.S. average of about 62%. Among adults in 21804, ~38% vote Democratic, ~30% Republican, and ~32% don't vote. The map below shows estimated turnout by block group.
How 21804 compares
Among zip codes within 15 miles, 21804 leans more Democratic than 12 of 16 neighbors.
21804 runs about 18 points more Republican than Maryland as a whole.
Politics vary noticeably by block within 21804. The northwest side runs the most Democratic (D+60) and the southeast side runs the most Republican (R+21), a spread of about 81 points.
Why 21804 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 21804, not a ranked or complete list of what matters most.
Density combined with diversity predicts Democratic voting. Non-Hispanic white share in 21804 is about 52%, about 20 points below the U.S. average of 72%. A high never-married share predicts Democratic voting, and about 41% of adults in 21804 have never been married, above 89% of zip codes.
Population density and Democratic lean
Places with high population density tend to lean Democratic; 21804, MD sits in the top quarter nationally on this measure.
Why turnout in 21804 looks the way it does
Turnout in 21804 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.