January 15 - The Pentagon Building is completed in Washington, D.C.
February 28 - The gun of the American warship Princeton explodes and kills the Secretary of State, the Secretary of the Navy and twelve crew members.
May 23 - The English Crown grants a new charter to the London Company to be titled the Virginia Company and increases its powers of government in the American colony.
June 27 - Brigham Young becomes the leader of the Mormons.
August 5 - The cornerstone is laid for the Statue of Liberty on Bedloe's Island, New York.
September 5 - Iron ore is discovered in the Mesabi Mountains in Minnesota.
November 5 - A California grizzly bear undergoes a successful cataract operation at the Zoological Garden.
December 4 - James K. Polk is elected to be the 11th U.S. President.
December 11 - The first dental anesthetic is used for a tooth extraction on Horace Wells.
