July 25 - Joaquin Murietta, the famous Californio bandit known as "Robin Hood of El Dorado", is killed.
October 4 - Crimean War: The Ottoman Empire declares war on Russia.
November 30 - Crimean War: Battle of Sinop — The Imperial Russian Navy under Pavel Nakhimov destroys the Ottoman fleet under Osman Pasha at Sinop, a sea port in northern Turkey.
December 30 - Gadsden Purchase: The United States buys land from Mexico to facilitate railroad building in the Southwest.
December 30 - A dinner party is held inside a life-size model of an Iguanodon created by Benjamin Waterhouse Hawkins and Sir Richard Owen in south London.
