15221 is a Democratic stronghold. About 84% of voters here vote Democratic and 16% Republican.
About 76% of adults in 15221 typically vote, above the U.S. average of about 62%. Among adults in 15221, ~64% vote Democratic, ~12% Republican, and ~24% don't vote. The map below shows estimated turnout by block group.
How 15221 compares
Among zip codes within 15 miles, 15221 leans more Democratic than 97 of 102 neighbors.
15221 runs about 70 points more Democratic than Pennsylvania as a whole. Pennsylvania is roughly evenly split, and 15221 sits clearly on the Democratic side.
Politics vary noticeably by block within 15221. The north side is the most Democratic-leaning (D+88) and the southeast side is the least Democratic-leaning (D+44), a spread of about 43 points.
Why 15221 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 15221, not a ranked or complete list of what matters most.
Dense areas vote Democratic. About 98% of residents in 15221 live in densely developed areas, about 62 points above the U.S. average of 36%. High college attainment predicts Democratic voting, and 15221 sits in the top quarter (about 41%, above 82% of zip codes). 15221 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; 15221, 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 15221 looks the way it does
Turnout in 15221 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.