Events
- 1808 - John Jacob Astor incorporates the American Fur Company.
- 1830 - The Church of Jesus Christ of Latter-day Saints is organized by Joseph Smith, Jr. and others at Fayette, New York.
- 1832 - Indian Wars: Black Hawk War begins - The Sauk warrior Black Hawk enters into war with the United States.
- 1860 - Joseph Smith III, creates the Reorganized Church of Jesus Christ of Latter Day Saints by reorganizing the previous church organized by his father, Joseph Smith, Jr.
- 1862 - American Civil War: Battle of Shiloh begins - In Tennessee, forces under Union General Ulysses S. Grant meet Confederate troops led by General Albert Sidney Johnston.
- 1865 - American Civil War: Battle of Sayler's Creek - Confederate General Robert E. Lee's Army of Northern Virginia fights its last major battle while in retreat from Richmond, Virginia.
- 1866 - The Grand Army of the Republic, an American patriotic organization composed of Union veterans of the American Civil War, is founded. It lasts until 1956.
- 1893 - Salt Lake Temple of The Church of Jesus Christ of Latter-day Saints dedicated by Wilford Woodruff.
- 1909 - Robert Peary and Matthew Henson allegedly reach the North Pole.
- 1917 - World War I: United States declares war on Germany (see Wilson's address to Congress).
- 1926 - Walter Varney Airlines makes first commercial flight (Varney is the root company of United Airlines).
- 1930 - James Dewar invents the Hostess cream-filled twinkie.
- 1936 - Tupelo-Gainesville tornado outbreak: Another tornado from the same storm system as the Tupelo tornado hits Gainesville, Georgia, killing 203.
- 1947 - The first Tony Awards are presented for theatrical achievements.
- 1965 - Launch of Early Bird, the first communications satellite to be placed in synchronous orbit.
- 1968 - In Richmond, Indiana's downtown district, a double explosion kills 41 and injures 150.
- 1970 - Newhall Incident: Four California Highway Patrol officers are killed.
- 1972 - Vietnam War: Easter Offensive - American forces begin sustained air strikes and naval bombardments.
- 1973 - Launch of Pioneer 11 spacecraft.