Pennsylvania's fourth congressional district, effective January 3, 2023, encompasses the majority of Montgomery County and most of Berks County northeast of Reading in southeastern Pennsylvania. In the 2020 redistricting cycle, the Pennsylvania district pushed northwards, further into Berks County, effective with the 2022 elections. The area has been represented by Democrat Madeleine Dean since 2019.

Montgomery County, colloquially referred to as Montco, is a county in the Commonwealth of Pennsylvania. As of the 2020 census, the population of the county was 856,553, making it the third-most populous county in Pennsylvania after Philadelphia and Allegheny counties. The county is part of the Southeast Pennsylvania region of the state.