Heidelberg leans slightly Democratic by roughly 10 points: about 55% of voters vote Democratic and 45% Republican.
About 76% of adults in Heidelberg typically vote, above the U.S. average of about 62%. Among adults in Heidelberg, ~42% vote Democratic, ~34% Republican, and ~24% don't vote. The map below shows estimated turnout by block group.
How Heidelberg compares
Among cities within 25 miles, Heidelberg leans more Democratic than 197 of 245 neighbors.
Heidelberg runs about 12 points more Democratic than Pennsylvania as a whole. Pennsylvania is roughly evenly split, and Heidelberg sits clearly on the Democratic side.
Why Heidelberg leans the way it does
This analysis examined 14,881 data points per city to find what predicts political lean and turnout. The items below are a few correlations that stood out for Heidelberg, not a ranked or complete list of what matters most.
Dense areas vote Democratic. More than 99% of residents in Heidelberg live in densely developed areas, about 63 points above the U.S. average of 36%. A high never-married share predicts Democratic voting, and about 44% of adults in Heidelberg have never been married, above 96% of cities. Heidelberg 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; Heidelberg, PA sits in the top tenth nationally on this measure.
Why turnout in Heidelberg looks the way it does
Areas with high high-school completion turn out at higher rates. About 98% of adults in Heidelberg have completed high school, about 6 points above the Pennsylvania average of 91%. Learn more about the findings and methodology on the political spectrum map.
Nearby Cities
- Carnegie, PA D+7
- Presto, PA R+5
- Rosslyn Farms, PA D+16
- Green Tree, PA D+10
- Dormont, PA D+39
- Rennerdale, PA R+12
- Thornburg, PA D+18
- Crafton, PA D+19
- Bridgeville, PA Even
- Ingram, PA D+14
Cities with Similar Populations
- Welcome Valley, TX R+73
- Beech Mountain, NC R+22
- Waldrup, MS R+22
- Ramah, NM D+14
- Bennington, OK R+74
- Eudora, MS R+66
- Broseley, MO R+71
- Rosiclare, IL R+53
- Eastport, ME D+22
- Walkerville, MI R+47
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.