[1] A map released on December 13, 2011, effectively merged the 4th and 12th congressional districts, represented by Democrats Jason Altmire and Mark Critz.

Results of the 2012 United States House of Representatives elections in Pennsylvania by district:[4] Pennsylvania's 1st congressional district includes primarily central and South Philadelphia, the City of Chester, the Philadelphia International Airport, and other small sections of Delaware County.

Labor unions Organizations Newspapers Organizations Pennsylvania's 2nd congressional district includes predominantly African American sections of the city of Philadelphia—West Philadelphia, North Philadelphia, and Northwest Philadelphia—in addition to parts of South Philadelphia, Center City, and western suburbs such as Lower Merion Township in Montgomery County.

Labor unions Organizations Newspapers Organizations Pennsylvania's 3rd congressional district is located in the northwestern part of the state and includes the cities of Erie, Sharon, Hermitage, Butler and Meadville.

Organizations Labor unions Organizations Pennsylvania's 6th congressional district is located in southeastern part of the state with a combination some of very affluent suburban areas of Philadelphia and sparsely populated rural areas.

Labor unions Organizations Newspapers Labor unions Organizations Pennsylvania's 8th congressional district is located in Bucks County, along with portions of Montgomery County.

Representatives Pennsylvania's 10th congressional district is located in the central and northeast regions of the state.

Organizations Organizations Labor unions Organizations Newspapers Jason Altmire Democratic Keith Rothfus Republican Pennsylvania's 12th congressional district is located in southwestern Pennsylvania, and consists of all of Beaver County, and parts of Allegheny, Cambria, Lawrence, Somerset, and Westmoreland counties.

Representatives Organizations Newspapers Individuals Newspapers Pennsylvania's 13th congressional district is located in Southeastern Pennsylvania, covering eastern Montgomery County and Northeast Philadelphia.

Democrat Allyson Schwartz, who had represented Pennsylvania's 13th congressional district since 2005, sought re-election.

Incumbent Republican Joe Pitts, who had represented the district since 1997, faced Democrat Aryanna C. Strader.

Democrat Tim Holden, who had represented Pennsylvania's 17th congressional district since 2003, ran for re-election.

[109] Pennsylvania Republicans, who controlled the redistricting process after the 2010 United States census, drew this district to be much more Democratic, taking in parts of Scranton and Wilkes Barre.

Holden's opposition to the Patient Protection and Affordable Care Act and climate change legislation are believed to have contributed to his defeat by a more liberal opponent.