18103 leans slightly Democratic by roughly 10 points: about 55% of voters vote Democratic and 45% Republican.
About 68% of adults in 18103 typically vote, above the U.S. average of about 62%. Among adults in 18103, ~37% vote Democratic, ~31% Republican, and ~32% don't vote. The map below shows estimated turnout by block group.
How 18103 compares
Among zip codes within 15 miles, 18103 leans more Democratic than 46 of 53 neighbors.
18103 runs about 12 points more Democratic than Pennsylvania as a whole. Pennsylvania is roughly evenly split, and 18103 sits clearly on the Democratic side.
Politics vary noticeably by block within 18103. The north side runs the most Democratic (D+20) and the southeast side runs the most Republican (R+10), a spread of about 31 points.
Why 18103 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 18103, not a ranked or complete list of what matters most.
Dense areas vote Democratic. About 86% of residents in 18103 live in densely developed areas, about 50 points above the U.S. average of 36%. A high never-married share predicts Democratic voting, and about 34% of adults in 18103 have never been married, above 77% of zip codes. 18103 runs against the grain of Pennsylvania, a Democratic-leaning outlier in a roughly evenly split state.
Population density and Democratic lean
Places with high population density tend to lean Democratic; 18103, PA sits in the top tenth nationally on this measure.
Why turnout in 18103 looks the way it does
Turnout in 18103 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 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.