The presidential election becomes official with the announcement from the Electoral College
The electoral votes having been ceremonially counted in the House of Representatives in a joint session of Congress, Vice-President John C. Breckinridge made the official announcement that Abraham Lincoln and Hannibal Hamlin "having received a majority of the whole number of electoral votes" had been duly elected as president and vice-president of the United States and would serve a four year term beginning on March 4, 1861. (By John Osborne)
Frank Moore, The Rebellion Record: A Diary of American Events, with Documents, Narratives, Illustrative Incidents, Poetry, Etc. (New York: G.P.Putnam, 1861), I: 31.