! | colspan=3 | None | | New seat.New member elected.Democratic gain. | nowrap | |} Mississippi Mississippi gained 2 seats, going from 2 to 4 members. Elections were held at-large on a general ticket November 6–7, 1843, after the March 4, 1843 beginning of the term. Due to a banking crisis in Mississippi, the state Democratic party was split into two factions; the Redemptions, which favored the repudiation of bank bonds, and Anti-Redemptions, which opposed it. |- ! rowspan=4 | (4 seats) | Jacob Thompson | | Democratic | 1839 | Incumbent re-elected. | nowrap rowspan=4 | |- | William M. Gwin | | Democratic | 1841 | | Incumbent retired.New member elected.Democratic hold. |- | colspan=3 | None (new district) | | New member elected.Democratic gain. |- | colspan=3 | None (new district) | | New member elected.Democratic gain. |} Missouri Missouri gained 3 seats, going from 2 to 5 members. Elections were held at-large on a general ticket August 1, 1842. |- ! rowspan=5 | | | | | | rowspan=5 nowrap | |- | | | | |- | | | | |- | | | | |- | | | | |} New Hampshire New Hampshire lost 1 seat, going from 5 to 4 members. Elections were held at-large on a general ticket March 3, 1843. |- ! rowspan=4 | | |- | |- | |- | |} New Jersey New Jersey lost 1 seats, going from 6 to 5 members. Elections were held from districts October 8, 1842, having previously elected them at-large. |- ! | Joseph Fitz Randolph | | Whig | 1836 | | Incumbent retired.New member elected.Democratic gain. | nowrap | |- ! | John B. Aycrigg | | Whig | 18361838 1840 | | Incumbent retired.New member elected.Democratic gain. | nowrap | |- ! | William Halstead | | Whig | 18361838 1840 | | Unknown if incumbent retired or lost.New member elected.Democratic gain. | nowrap | |- ! | John Patterson Bryan Maxwell | | Whig | 18361838 1840 | | Unknown if incumbent retired or lost.New member elected.Democratic gain. | nowrap | |- ! rowspan=2 | | Charles C. Stratton | | Whig | 18361838 1840 | | Incumbent retired.New member elected.Whig hold. | rowspan=2 nowrap | |- | Thomas Jones Yorke | | Whig | 18361838 1840 | | Unknown if incumbent retired or lost.Whig loss. |}