Elections to the United States House of Representatives were held in Pennsylvania on October 13, 1812, for the 13th Congress.
In the previous election, 17 Democratic-Republicans and 1 Federalist had been elected to represent Pennsylvania.
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.
Sixteen incumbents (all Democratic-Republicans) ran for re-election, of whom 14 were re-elected. The incumbents James Milnor (F) of the and Joseph Lefever (DR) of the old 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.
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 , died on December 30, 1812, and Abner Lacock (DR), re-elected to the , 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 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
John Gloninger (F) of the and John M. Hyneman (DR) of the 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
Jonathan Roberts (DR) of the resigned February 24, 1814, upon being elected to the Senate and James Whitehill (DR) of the 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.