Pennsylvania's fifth congressional district encompasses all of Delaware County, an exclave of Chester County, a small portion of southern Montgomery County and a section of southern Philadelphia. Democrat Mary Gay Scanlon represents the district.

Prior to 2018, the fifth district was located in north-central Pennsylvania and was the largest in area, and therefore least densely populated, of all of Pennsylvania's congressional districts. It was Republican-leaning and represented by Glenn Thompson (R). However, in February 2018, the Supreme Court of Pennsylvania redrew this district after ruling the previous congressional district map unconstitutional due to partisan gerrymandering, assigning its number to a more left-leaning district in southeastern Pennsylvania for the 2018 elections and representation thereafter–essentially, a successor to the old seventh district. Most of Thompson's territory became a new, heavily Republican 15th district.^[2] He was re-elected there.

The 5th district is mostly suburban, but contains some urban and rural areas as well. The entirety of Delaware County and the majority of both the Main Line Suburbs and South Philadelphia are part of this district. The district is fairly diverse compared to others in Pennsylvania, and is roughly 25% African American.

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Pennsylvania's 5th congressional district is located in the southeastern corner of Pennsylvania and includes all or part of the following four counties:^[3]

• Chester
• Delaware
• Montgomery
• Philadelphia

Cities in this district include:

• Philadelphia
• Chester

District created in 1791 from the at-large district.

• 2003–2013
• 2013–2019
• 2019–2023

• List of United States congressional districts
• Pennsylvania's congressional districts