| January 9 | Clipper Guiding Star disappears in Atlantic, 480 dies |
| January 31 | Western railroads blocked by snow |
| February 3 | Wisconsin Supreme Court declares U.S. Fugitive Slave Law unconstitutional |
| February 4 | Soldiers shoot Jewish families in Coro, Venezuela |
| February 5 | British government of Palmerston forms |
| February 10 | U.S. citizenship laws amended all children of U.S. parents born abroad granted U.S. citizenship |
| February 24 | U.S. Court of Claims forms for cases against government |
| March 2 | Aleksandr Romanov becomes tsar of Russia |
| March 3 | Congress approves $30,000 to test camels for military use |
| March 3 | Congress authorizes registered mail |
| March 6 | Gustave Flaubert writes goodbye to Louise Colet |
| March 8 | 1st train crosses 1st U.S. railway suspension bridge, Niagara Falls |
| March 15 | Louisiana establishes 1st health board to regulate quarantine |
| March 24 | Manhattan Kansas founded as New Boston Kansas |
| March 27 | Abraham Gesner patents kerosene |
| April 21 | 1st train crosses Mississippi River's 1st bridge, Rock Island, Illinois to Davenport Iowa |
| April 26 | Composer Gioacchino Rossini leaves Italy |
| April 28 | 1st veterinary college in U.S. incorporated in Boston |
| May 3 | Antwerp-Rotterdam railway opens |
| May 5 | New York City regains Castle Clinton, to be used for immigration |
| June 1 | U.S. adventurer Wm Walker conquers Nicaragua, reestablishes slavery |
| June 5 | Anti-foreign anti-Roman Catholic Know-Nothing Party's 1st convention |
| June 13 | Opera "Les Vapres Sicilenne" is produced (Paris) |
| June 17 | Heavy French/British bombing of Sebastopol, 2000+ killed |
| June 20 | Commissioners appointed to lay out San Francisco streets west of Larkin |
| July 20 | 1st train from Rotterdam to Utrecht in Netherlands |
| July 31 | Hottest July in Stockholm since at least 1756 (21.4 degrees C avg) |
| August 1 | Castle Clinton in New York City opens as 1st U.S. receiving station for immigrants |
| August 3 | Rotterdam-Gouda railway opens |
| August 4 | John Bartlett publishes "Familiar Quotations" |
| August 9 | Battle of Acapulco during Mexican Liberal uprising |
| September 8 | Crimean war - assault of Malakof Tower under Mac-Mahon |
| September 27 | George F Bristow's "Rip Van Winkle," 2nd American opera, opens in New York City |
| October 9 | Isaac Singer patents sewing machine motor |
| October 9 | Joshua Stoddard of Worcester, Mass patents 1st calliope |
| October 17 | Bessemer steelmaking process patented |
| October 18 | Franz Liszt's "Prometheus," premieres |
