| Incumbent re-elected. | nowrap | |- ! | James Monroe | | 1870 | | Incumbent retired.New member elected.Republican hold. | nowrap | |- ! | James A. Garfield | | 1862 | | Incumbent retired to run for U.S. President.New member elected.Republican hold. | nowrap | |- ! | Amos Townsend | | 1876 | Incumbent re-elected. | nowrap | |} Oregon Oregon held its election early on June 7, 1880. |- ! | John Whiteaker | | 1878 | | Incumbent lost re-election.New member elected.Republican gain. | nowrap | |} Pennsylvania |- ! | Henry H. Bingham | | 1878 | Incumbent re-elected. | nowrap | |- ! | Charles O'Neill | | 1872 | Incumbent re-elected. | nowrap | |- ! | Samuel J. Randall | | 1862 | Incumbent re-elected. | nowrap | |- ! | William D. Kelley | | 1860 | Incumbent re-elected. | nowrap | |- ! | Alfred C. Harmer | | 1876 | Incumbent re-elected. | nowrap | |- ! | William Ward | | 1876 | Incumbent re-elected. | nowrap | |- ! | William Godshalk | | 1878 | Incumbent re-elected. | nowrap | |- ! | Hiester Clymer | | 1872 | | Incumbent retired.New member elected.Democratic hold. | nowrap | |- ! | A. Herr Smith | | 1872 | Incumbent re-elected. | nowrap | |- ! | Reuben K. Bachman | | 1878 | | Incumbent retired.New member elected.Democratic hold. | nowrap | |- ! | Robert Klotz | | 1878 | Incumbent re-elected. | nowrap | |- ! | Hendrick B. Wright | | Greenback | 1876 | | Incumbent lost re-election.New member elected.Republican gain. | nowrap | |- ! | John W. Ryon | | 1878 | | Incumbent lost re-election.New member elected.Greenback gain. | nowrap | |- ! | John W. Killinger | | 1876 | | Incumbent retired.New member elected.Republican hold. | nowrap | |- ! | Edward Overton Jr. | | 1876 | | Incumbent lost renomination.New member elected.Republican hold. | nowrap | |- ! | John I. Mitchell | | 1876 | | Incumbent retired to run for U.S. senator.New member elected.Republican hold. | nowrap | |- ! | Alexander H. Coffroth | | 1878 | | Incumbent lost re-election.New member elected.Republican gain. | nowrap | |- ! | Horatio G. Fisher | | 1878 | Incumbent re-elected. |