20166 leans Democratic by roughly 26 points: about 63% of voters vote Democratic and 37% Republican.
About 66% of adults in 20166 typically vote, near the U.S. average of about 62%. Among adults in 20166, ~42% vote Democratic, ~24% Republican, and ~34% don't vote. The map below shows estimated turnout by block group.
How 20166 compares
Among zip codes within 15 miles, 20166 leans more Democratic than 16 of 37 neighbors.
20166 runs about 21 points more Democratic than Virginia as a whole.
Politics vary noticeably by block within 20166. The east side is the most Democratic-leaning (D+29) and the south side is the least Democratic-leaning (D+9), a spread of about 20 points.
Why 20166 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 20166, not a ranked or complete list of what matters most.
Areas with high college attainment vote Democratic. About 65% of adults in 20166 hold a bachelor's degree, about 36 points above the U.S. average of 28%. Dense areas vote Democratic, and 20166 sits in the top fifth on density (about 91%, above 88% of zip codes). A high never-married share predicts Democratic voting, and about 36% of adults in 20166 have never been married, above 81% of zip codes.
Preventive-care access and voter turnout
Places with strong routine preventive-care access tend to turn out at a higher rate; 20166, VA sits in the top quarter nationally on this measure. Dental visits do not drive turnout; the rate reflects income, insurance, and healthcare access, which line up with who votes.
Why turnout in 20166 looks the way it does
Areas with strong routine healthcare access turn out at higher rates. 20166 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 69%, about 9 points above the U.S. average of 60%. 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 Virginia Department 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.