Delaware County, PA Political Map | Democrat & Republican Areas in Delaware County

By the BestNeighborhood data science team. Last updated May 2026.

Delaware County leans Democratic by roughly 28 points: about 64% of voters vote Democratic and 36% Republican.

 

About 81% of adults in Delaware County typically vote, above the U.S. average of about 62%. Among adults in Delaware County, ~52% vote Democratic, ~29% Republican, and ~19% don't vote. The map below shows estimated turnout by block group.

How Delaware County compares

Among counties within 50 miles, Delaware County leans more Democratic than 10 of 14 neighbors.

Delaware County runs about 29 points more Democratic than Pennsylvania as a whole. Pennsylvania is roughly evenly split, and Delaware County sits clearly on the Democratic side.

Politics vary noticeably by city within Delaware County. The northeast side runs the most Democratic (D+46) and the southeast side runs the most Republican (R+4), a spread of about 50 points.

Why Delaware County leans the way it does

This analysis examined 14,881 data points per county to find what predicts political lean and turnout. The items below are a few correlations that stood out for Delaware County, not a ranked or complete list of what matters most.

Dense areas vote Democratic. About 89% of residents in Delaware County live in densely developed areas, about 53 points above the U.S. average of 36%. High college attainment predicts Democratic voting, and Delaware County sits in the top quarter (about 42%, above 93% of counties). A high never-married share predicts Democratic voting, and about 38% of adults in Delaware County have never been married, above 91% of counties.

Paved land cover and Democratic lean

Places with extensive paved surfaces tend to lean Democratic; Delaware County, 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 Delaware County looks the way it does

Areas with strong routine healthcare access turn out at higher rates. Delaware County is in the top quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. The dental-visit rate here is about 66%, about 6 points above the U.S. average of 60%. High high-school completion lines up with higher turnout, and about 94% of adults in Delaware County have completed high school, above 83% of counties. Learn more about the findings and methodology on the political spectrum map.

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.