18104 leans slightly Democratic by roughly 14 points: about 57% of voters vote Democratic and 43% Republican.
About 79% of adults in 18104 typically vote, above the U.S. average of about 62%. Among adults in 18104, ~45% vote Democratic, ~34% Republican, and ~21% don't vote. The map below shows estimated turnout by block group.
How 18104 compares
Among zip codes within 15 miles, 18104 leans more Democratic than 49 of 53 neighbors.
18104 runs about 16 points more Democratic than Pennsylvania as a whole. Pennsylvania is roughly evenly split, and 18104 sits clearly on the Democratic side.
Politics vary noticeably by block within 18104. The east side is the most Democratic-leaning (D+38) and the north side is the least Democratic-leaning (Even), a spread of about 37 points.
Why 18104 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 18104, not a ranked or complete list of what matters most.
Dense areas vote Democratic. About 93% of residents in 18104 live in densely developed areas, about 56 points above the U.S. average of 36%. High college attainment predicts Democratic voting, and 18104 sits in the top quarter (about 48%, above 88% of zip codes). A high never-married share predicts Democratic voting, and about 35% of adults in 18104 have never been married, above 79% of zip codes.
Preventive-care access and voter turnout
Places with strong routine preventive-care access tend to turn out at a higher rate; 18104, PA 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 18104 looks the way it does
Areas with strong routine healthcare access turn out at higher rates. 18104 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 68%, about 8 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 Pennsylvania Department of State, Bureau 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.