15021 leans heavily Republican by roughly 40 points: about 30% of voters vote Democratic and 70% Republican.
About 73% of adults in 15021 typically vote, above the U.S. average of about 62%. Among adults in 15021, ~22% vote Democratic, ~51% Republican, and ~27% don't vote. The map below shows estimated turnout by block group.
How 15021 compares
Among zip codes within 15 miles, 15021 leans more Republican than 24 of 40 neighbors.
15021 runs about 39 points more Republican than Pennsylvania as a whole.
Politics vary noticeably by block within 15021. The southwest side is the most Republican-leaning (R+49) and the east side is the least Republican-leaning (R+32), a spread of about 17 points.
Why 15021 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 15021, not a ranked or complete list of what matters most.
Areas with a high white share and below-average college attainment vote Republican. In 15021, about 93% of residents are non-Hispanic white, about 21 points above the U.S. average of 72%; about 19% of adults hold a bachelor's degree, about 7 points below the Pennsylvania average of 26%.
Overall lean vs. state and nation
15021, PA leans Republican compared with its state and the country.
Why turnout in 15021 looks the way it does
Turnout in 15021 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.