20640 leans Democratic by roughly 26 points: about 63% of voters vote Democratic and 37% Republican.
About 69% of adults in 20640 typically vote, above the U.S. average of about 62%. Among adults in 20640, ~43% vote Democratic, ~26% Republican, and ~31% don't vote. The map below shows estimated turnout by block group.
How 20640 compares
Among zip codes within 15 miles, 20640 leans more Democratic than 12 of 36 neighbors.
Politically, 20640 sits close to the rest of Maryland.
Politics vary noticeably by block within 20640. The west side runs the most Democratic (D+41) and the east side runs the most Republican (R+11), a spread of about 53 points.
Why 20640 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 20640, not a ranked or complete list of what matters most.
Areas with many never-married adults vote Democratic. About 39% of adults in 20640 have never been married, modestly above similar-sized zip codes (around 32%).
Population density and Democratic lean
Places with high population density tend to lean Democratic; 20640, MD sits above the national average on this measure.
Why turnout in 20640 looks the way it does
Turnout in 20640 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.