| | Incumbent lost re-election.New member elected.Democratic gain. | nowrap | |- ! | Samuel F. Swope | | Know Nothing | 1855 | | Incumbent retired.New member elected.Democratic gain. | nowrap | |} Louisiana |- ! | George Eustis Jr. | | Know Nothing | 1855 | Incumbent re-elected. | nowrap | |- ! | Miles Taylor | | Democratic | 1855 | Incumbent re-elected. | nowrap | |- ! | Thomas G. Davidson | | Democratic | 1855 | Incumbent re-elected. | nowrap | |- ! | John M. Sandidge | | Democratic | 1855 | Incumbent re-elected. | nowrap | |} Maine |- ! | John M. Wood | | Republican | 1854 | Incumbent re-elected. | nowrap | |- ! | John J. Perry | | Republican | 1854 | | Incumbent retired.New member elected.Republican hold. | nowrap | |- ! | Ebenezer Knowlton | | Republican | 1854 | | Incumbent retired.New member elected.Republican hold. | nowrap | |- ! | Samuel P. Benson | | Republican | 1852 | | Incumbent retired.New member elected.Republican hold. | nowrap | |- ! | Israel Washburn Jr. | | Republican | 1850 | Incumbent re-elected. | nowrap | |- ! | Thomas J. D. Fuller | | Democratic | 1848 | | Incumbent retired.New member elected.Republican gain. | nowrap | |} Maryland |- ! |- ! |- ! |- ! |- ! |- ! |} Massachusetts |- ! | Robert B. Hall | | Know Nothing | 1854 | | Incumbent re-elected to a new party.Republican gain. | nowrap | |- ! | James Buffinton | | Know Nothing | 1854 | | Incumbent re-elected to a new party.Republican gain. | nowrap | |- ! | William S. Damrell | | Know Nothing | 1854 | | Incumbent re-elected to a new party.Republican gain. | nowrap | |- ! | Linus B. Comins | | Know Nothing | 1854 | | Incumbent re-elected to a new party.Republican gain. | nowrap | |- ! | Anson Burlingame | | Know Nothing | 1854 | | Incumbent re-elected to a new party.Republican gain. | nowrap | |- ! | Timothy Davis | | Know Nothing | 1854 | | Incumbent re-elected to a new party.Republican gain. | nowrap | |- ! | Nathaniel P. Banks | | Know Nothing | 1852 | | Incumbent re-elected to a new party.Republican