20818 is a Democratic stronghold. About 81% of voters here vote Democratic and 19% Republican.
About 98% of adults in 20818 typically vote, above the U.S. average of about 62%. Among adults in 20818, ~79% vote Democratic, ~19% Republican, and ~2% don't vote. The map below shows estimated turnout by block group.
How 20818 compares
Among zip codes within 15 miles, 20818 leans more Democratic than 77 of 128 neighbors.
20818 runs about 33 points more Democratic than Maryland as a whole.
Why 20818 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 20818, not a ranked or complete list of what matters most.
Areas with high college attainment vote Democratic. About 87% of adults in 20818 hold a bachelor's degree, about 59 points above the U.S. average of 28%. Dense areas vote Democratic, and 20818 sits in the top fifth on density (about 77%, above 82% of zip codes).
Park access and Democratic lean
Places with heavy park coverage tend to lean Democratic; 20818, MD sits in the top tenth nationally on this measure. Park access does not change how people vote; it tends to track denser, higher-income areas.
Why turnout in 20818 looks the way it does
Areas with strong routine healthcare access turn out at higher rates. 20818 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 79%, about 19 points above the U.S. average of 60%. Homeowners vote more often than renters, and about 95% of households in 20818 own their home, compared to around 70% in nearby zip codes. High high-school completion lines up with higher turnout, and more than 99% of adults in 20818 have completed high school, above 98% 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.