| Historically | Since 1950 | |||||
| Counties | % R Wins | Counties | % R Wins | |||
| Consist. Democrat | Greene | 15% | Consist. D. | Phileldelphia | 0% | |
| Mod Democrat | Fayette | 20% | Fayette | 8% | ||
| Washington | 20% | Greene | 8% | |||
| Westmoreland | 25% | Washington | 8% | |||
| Phileldelphia | 30% | Beaver | 15% | |||
| Allegheny | 35% | Lackawanna | 15% | |||
| Lackawanna | 35% | Westmoreland | 15% | |||
| Beaver | 40% | Mod. D. | Allegheny | 23% | ||
| Cambria | 40% | Cambria | 23% | |||
| Northhampton | 40% | Elk | 31% | |||
| Swing | Elk | 45% | Lawrence | 31% | ||
| Berks | 50% | Luzerne | 31% | |||
| Carbon | 50% | Carbon | 38% | |||
| Lawrence | 50% | Northhampton | 38% | |||
| Columbia | 55% | Swing | Armstrong | 46% | ||
| Fulton | 55% | Clearfield | 46% | |||
| Luzerne | 55% | Berks | 54% | |||
| York | 55% | Clinton | 54% | |||
| Mod Republican | Clearfield | 60% | Columbia | 54% | ||
| Northhumberland | 60% | Fulton | 54% | |||
| Armstrong | 65% | Mercer | 54% | |||
| Clinton | 65% | Northhumberland | 54% | |||
| Lehigh | 65% | York | 54% | |||
| Mercer | 65% | Mod. R. | Schuylkill | 62% | ||
| Schuylkill | 65% | Erie | 69% | |||
| Erie | 70% | Lehigh | 69% | |||
| Monroe | 70% | Somerset | 69% | |||
| Montour | 70% | Bucks | 77% | |||
| Clarion | 75% | Butler | 77% | |||
| Juniata | 75% | Clarion | 77% | |||
| Lycoming | 75% | Dauphin | 77% | |||
| Mifflin | 75% | Indiana | 77% | |||
| Adams | 80% | Juniata | 77% | |||
| Bedford | 80% | Lycoming | 77% | |||
| Butler | 80% | Mifflin | 77% | |||
| Centre | 80% | Monroe | 77% | |||
| Somerset | 80% | Montour | 77% | |||
| Consist. Republican | Blair | 85% | Consist. R. | Adams | 85% | |
| Bucks | 85% | Bedford | 85% | |||
| Crawford | 85% | Blair | 85% | |||
| Cumberland | 85% | Cameron | 85% | |||
| Dauphin | 85% | Centre | 85% | |||
| Franklin | 85% | Crawford | 85% | |||
| Indiana | 85% | Jefferson | 85% | |||
| Jefferson | 85% | Sullivan | 85% | |||
| Pike | 85% | Venango | 85% | |||
| Sullivan | 85% | Bradford | 92% | |||
| Cameron | 90% | Chester | 92% | |||
| Huntingdon | 90% | Cumberland | 92% | |||
| Perry | 90% | Delaware | 92% | |||
| Potter | 90% | Forest | 92% | |||
| Snyder | 90% | Franklin | 92% | |||
| Union | 90% | Huntingdon | 92% | |||
| Venango | 90% | Lancaster | 92% | |||
| Wyoming | 90% | Lebanon | 92% | |||
| Bradford | 95% | McKean | 92% | |||
| Chester | 95% | Montgomery | 92% | |||
| Delaware | 95% | Perry | 92% | |||
| Forest | 95% | Pike | 92% | |||
| Lancaster | 95% | Potter | 92% | |||
| Lebanon | 95% | Snyder | 92% | |||
| McKean | 95% | Susquehanna | 92% | |||
| Montgomery | 95% | Tioga | 92% | |||
| Susquehanna | 95% | Union | 92% | |||
| Tioga | 95% | Warren | 92% | |||
| Warren | 95% | Wayne | 92% | |||
| Wayne | 95% | Wyoming | 92% | |||