Mount Oliver leans heavily Democratic by roughly 42 points: about 71% of voters vote Democratic and 29% Republican.
About 63% of adults in Mount Oliver typically vote, near the U.S. average of about 62%. Among adults in Mount Oliver, ~45% vote Democratic, ~18% Republican, and ~37% don't vote. The map below shows estimated turnout by block group.
How Mount Oliver compares
Among cities within 25 miles, Mount Oliver leans more Democratic than 245 of 256 neighbors.
Mount Oliver runs about 43 points more Democratic than Pennsylvania as a whole. Pennsylvania is roughly evenly split, and Mount Oliver sits clearly on the Democratic side.
Politics vary noticeably by neighborhood within Mount Oliver. The north side is the most Democratic-leaning (D+49) and the southeast side is the least Democratic-leaning (D+31), a spread of about 18 points.
Why Mount Oliver 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 Mount Oliver, not a ranked or complete list of what matters most.
Dense areas vote Democratic. About 99% of residents in Mount Oliver 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 49% of adults in Mount Oliver have never been married, above 98% of cities. Mount Oliver 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; Mount Oliver, 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 Mount Oliver looks the way it does
Areas with limited routine healthcare access turn out at lower rates. Mount Oliver is in the bottom quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. The dental-visit rate here is about 45%, about 19 points below the Pennsylvania average of 64%. Learn more about the findings and methodology on the political spectrum map.
Nearby Cities
- Pittsburgh, PA R+2
- Brentwood, PA D+14
- Dormont, PA D+39
- Baldwin, PA D+3
- Green Tree, PA D+10
- Castle Shannon, PA D+10
- West Homestead, PA D+19
- Homestead, PA D+49
- Crafton, PA D+19
- Munhall, PA D+17
Cities with Similar Populations
- Curtice, OH R+35
- Watkins Glen, NY R+20
- Okemah, OK R+51
- Lovell, WY R+70
- Murchison, TX R+75
- Mescalero, NM D+42
- Flora, IN R+51
- East Rockingham, NC R+21
- Buffalo Gap, TX R+71
- Rosepine, LA R+75
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.