15203 is a Democratic stronghold. About 76% of voters here vote Democratic and 24% Republican.
About 72% of adults in 15203 typically vote, above the U.S. average of about 62%. Among adults in 15203, ~55% vote Democratic, ~17% Republican, and ~28% don't vote. The map below shows estimated turnout by block group.
How 15203 compares
Among zip codes within 15 miles, 15203 leans more Democratic than 86 of 100 neighbors.
15203 runs about 53 points more Democratic than Pennsylvania as a whole. Pennsylvania is roughly evenly split, and 15203 sits clearly on the Democratic side.
Politics vary noticeably by block within 15203. The east side is the most Democratic-leaning (D+58) and the southeast side is the least Democratic-leaning (D+44), a spread of about 14 points.
Why 15203 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 15203, not a ranked or complete list of what matters most.
Dense areas vote Democratic. About 89% of residents in 15203 live in densely developed areas, about 53 points above the U.S. average of 36%. High college attainment predicts Democratic voting, and 15203 sits in the top quarter (about 56%, above 92% of zip codes). 15203 runs against the grain of Pennsylvania, a Democratic-leaning outlier in a roughly evenly split state.
Paved land cover and Democratic lean
Places with extensive paved surfaces tend to lean Democratic; 15203, PA sits in the top tenth nationally on this measure. Paved ground does not change how people vote; it mostly reflects how urban and built-up a place is.
Why turnout in 15203 looks the way it does
Turnout in 15203 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.