1812 United States House of Representatives elections in Pennsylvania

Elections to the United States House of Representatives were held in Pennsylvania on October 13, 1812, for the 13th Congress.

Background
In the previous election, 17 Democratic-Republicans and 1 Federalist had been elected to represent Pennsylvania.

Congressional districts
Pennsylvania was divided at this time into 15 districts, 9 of which were single-member districts, five of which had two members, and one of which had four members. Following the 1810 census, Pennsylvania underwent redistricting. Most of the new districts had little correspondence to the former districts, for example, the old 3rd district was divided between the new 2nd, 3rd, and 7th districts. The 1st, 9th and 10th districts were unaltered, except for renumbering of the old 9th and 10th to 13th and 12th respectively, and the addition of a 4th seat to the 1st district.
 * The PA's 1st congressional district (4 seats) consisted of Delaware and Philadelphia Counties (including the City of Philadelphia)
 * The PA's 2nd congressional district (2 seats) consisted of Chester and Montgomery Counties
 * The PA's 3rd congressional district (2 seats) consisted of Dauphin and Lancaster County, Pennsylvania
 * The PA's 4th congressional district consisted of York County
 * The PA's 5th congressional district (2 seats) consisted of Adams, Cumberland and Franklin Counties
 * The PA's 6th congressional district (2 seats) consisted of Bucks, Lehigh, Northampton, and Wayne Counties
 * The PA's 7th congressional district consisted of Berks and Schuylkill Counties
 * The PA's 8th congressional district consisted of Bedford, Cambria, and Franklin Counties
 * The PA's 9th congressional district consisted of Centre, Clearfield, Huntingdon, McKean, and Mifflin Counties
 * The PA's 10th congressional district (2 seats) consisted of Bradford, Luzerne, Lycoming, Northumberland, Potter, Susquehanna, and Tioga Counties
 * The PA's 11th congressional district consisted of Armstrong, Indiana, Jefferson, and Westmoreland Counties
 * The PA's 12th congressional district consisted of Washington County
 * The PA's 13th congressional district consisted of Fayette and Greene Counties
 * The PA's 14th congressional district consisted of Allegheny and Butler Counties
 * The PA's 15th congressional district consisted of Beaver, Crawford, Erie, Mercer, Venango and Warren Counties

Election results
Sixteen incumbents (all Democratic-Republicans) ran for re-election, of whom 14 were re-elected. The incumbents James Milnor (F) of the PA's 1st congressional district and Joseph Lefever (DR) of the old PA's 3rd congressional district did not run for re-election. The two incumbents who lost re-election lost to members of the same party, while six of the seven open seats were won by Democratic-Republicans, a net increase of 5 seats for the Democratic-Republicans and no change for the Federalists.

Special elections for the first session
Three of the re-elected Representatives did not serve in the 13th Congress, two of whom did not finish their term in the 12th Congress either. John Smilie (DR), re-elected to the PA's 13th congressional district, died on December 30, 1812, and Abner Lacock (DR), re-elected to the PA's 15th congressional district, resigned February 24, 1813, after being elected to the Senate. Smilie was replaced by Isaac Griffin in a special election held February 16, 1813. The only record of that election is a manuscript which indicates he won by a 779-vote majority, but does not record the name(s) of his opponent(s) nor the total number of votes cast. Robert Whitehill (DR) of the PA's 5th congressional district died April 8, 1813. The election in the 5th district was held May 11, 1813, and in the 15th on May 4, 1813

Neither seat changed political parties, and both took their seats at the beginning of the 1st session of the 13th Congress, which lasted May 24 - August 2, 1813

Special elections for the 2nd session
John Gloninger (F) of the PA's 3rd congressional district and John M. Hyneman (DR) of the PA's 7th congressional district both resigned August 2, 1813, at the end of the 1st session. They were replaced in special elections held on October 12, 1813

Both took their seats December 6, 1813, at the start of the 2nd session. With Crouch's victory in the 3rd district, the sole Federalist-held seat in Pennsylvania changed to Democratic-Republican control, thus Pennsylvania's delegation was completely Democratic-Republican during the 2nd session, which lasted December 6, 1813 - April 18, 1814

Special elections for the third session
Jonathan Roberts (DR) of the PA's 2nd congressional district resigned February 24, 1814, upon being elected to the Senate and James Whitehill (DR) of the PA's 3rd congressional district resigned September 1, 1814. Both were replaced in a special election held October 11, 1814, the same day as the 1814 congressional elections.

Both seats changed from Democratic-Republican to Federalist control, so that for the 3rd session, Pennsylvania's delegation was 21 Democratic-Republicans and 2 Federalists.