Pennsylvania's 4th congressional district

Pennsylvania's fourth congressional district, effective January 3, 2019, encompasses the majority of Montgomery County and a small sliver of Berks County in southeastern Pennsylvania, and is represented by Democrat Madeleine Dean. From 2013 to 2018, the district was in the south-central part of the state, covering all of Adams and York counties, as well as parts of Cumberland and Dauphin counties, with representation by Republican Scott Perry.

From 2003 to 2013 the district included suburbs of Pittsburgh as well as Beaver County, Lawrence County, and Mercer County. The district had a slight Democratic registration edge, although it had voted for Republicans in several federal elections over the 2000s decade, including for President George W. Bush in 2000 and 2004, as well as Lynn Swann for governor in 2006. The heart of the district was a string of mostly white and middle class suburbs. Plum and Murrysville, two large and mainly residential boroughs, are the main towns in the suburban portion of the district that lies to the east of the city. Also included were the many suburban areas that make up northern Allegheny County and southern Butler County, Pennsylvania, including the larger communities of McCandless and Franklin Park, as well as several exclusive suburbs that have long been home to Pittsburgh's old money elite, including Fox Chapel and Sewickley. The northern suburbs had a generally moderate voting populace, which trends Democratic but makes up the swing vote, especially in races for national office. Further north, the district took on a different character. The suburban areas of Beaver County are somewhat less affluent and were heavily labor Democratic. The areas of Lawrence County and Mercer County had a more rural feel, but also had a union Democrat center within the city of New Castle.

Wikipedia