Pennsylvania's 12th congressional district is located in southwestern Pennsylvania, including Pittsburgh and much of Allegheny County, as well as some of Westmoreland County. Since January 3, 2023, it has been represented by Summer Lee.

Pennsylvania's 10th congressional district is located in the south-central region of the state. It encompasses all of Dauphin County as well as parts of Cumberland County and York County. The district includes the cities of Harrisburg and York. Prior to 2019, the district was located in the northeastern part of the state. The Supreme Court of Pennsylvania redrew the district in 2018 after ruling the previous map unconstitutional because of gerrymandering. The court added State College to the old district's boundaries while removing some Democratic-leaning areas and redesignated it the twelfth district; an area encompassing Harrisburg and York was numbered as the "10th". The new tenth district is represented by Republican Scott Perry, who previously represented the old fourth district.