18109 leans slightly Democratic by roughly 14 points: about 57% of voters vote Democratic and 43% Republican.
About 56% of adults in 18109 typically vote, below the U.S. average of about 62%. Among adults in 18109, ~32% vote Democratic, ~24% Republican, and ~44% don't vote. The map below shows estimated turnout by block group.
How 18109 compares
Among zip codes within 15 miles, 18109 leans more Democratic than 45 of 51 neighbors.
18109 runs about 16 points more Democratic than Pennsylvania as a whole. Pennsylvania is roughly evenly split, and 18109 sits clearly on the Democratic side.
Politics vary noticeably by block within 18109. The southwest side runs the most Democratic (D+27) and the northwest side runs the most Republican (R+2), a spread of about 29 points.
Why 18109 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 18109, not a ranked or complete list of what matters most.
Dense areas vote Democratic. About 90% of residents in 18109 live in densely developed areas, about 54 points above the U.S. average of 36%. A high never-married share predicts Democratic voting, and about 43% of adults in 18109 have never been married, above 91% of zip codes. 18109 runs against the grain of Pennsylvania, a Democratic-leaning outlier in a roughly evenly split state.
Walkability and Democratic lean
Places with a highly walkable street grid tend to lean Democratic; 18109, PA sits in the top tenth nationally on this measure. A walkable street grid does not change how people vote; it mostly reflects how urban a place is.
Why turnout in 18109 looks the way it does
Renters vote less often than owners. About 46% of households in 18109 rent, about 21 points above the U.S. average of 25%. Low high-school completion lines up with lower turnout, and about 80% of adults in 18109 have completed high school, below 90% 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 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.