Events
- 1775 – American Revolutionary War: Fort Ticonderoga is taken by a small force led by Ethan Allen and Colonel Benedict Arnold.
- 1775 – American Revolutionary War: Representatives from the 13 colonies of the United States meet in Philadelphia and raise the Continental Army to defend the new republic. They place it under command of George Washington of Virginia.
- 1801 – First Barbary War: The Barbary pirates of Tripoli declare war on the United States.
- 1837 – Panic of 1837: New York City banks fail, and unemployment reaches record levels.
- 1865 – American Civil War: Jefferson Davis is captured by Union troops near Irwinville, Georgia.
- 1865 – American Civil War: Union soldiers ambush and mortally wound Confederate raider William Quantrill in Kentucky, who lingers until his death on June 6.
- 1869 – The First Transcontinental Railroad, linking the eastern and western United States, is completed at Promontory Summit, Utah (not Promontory Point, Utah) with the golden spike.
- 1872 – Victoria Woodhull becomes the first woman nominated for President of the United States.
- 1908 – Mother's Day is observed for the first time in Grafton, West Virginia, United States).
- 1922 – The United States annexes the Kingman Reef.
- 1924 – J. Edgar Hoover is appointed the Director of the U.S. Federal Bureau of Investigation, and remains so until his death in 1972.
- 1954 – Bill Haley & His Comets release "Rock Around the Clock", the first rock and roll record to reach number one on the charts.
- 1960 – The nuclear submarine USS Triton completes the first underwater circumnavigation of the earth.
- 1970 – The Boston Bruins win their first Stanley Cup since 1941 when Bobby Orr makes an overtime winning goal followed by a leap in the air that would become one of the most famous photographs in ice hockey ("The Goal").
- 1996 – Excel Communications, Inc. becomes the youngest company ever to join the New York Stock Exchange (NYSE), trading under the symbol (ECI).
- 1996 – A "rogue storm" near the summit of Mount Everest kills eight climbers, making this the deadliest day in the mountain's history. Among the dead are experienced climbers Rob Hall and Scott Fischer, both of whom were leading paid expeditions to the summit.
- 2003 – Record shattering tornado activity during the May 2003 tornado outbreak sequence.
- 2005 – A hand grenade allegedly thrown by Vladimir Arutinian lands about 65 feet (20 metres) from United States President George W. Bush while he was giving a speech to a crowd in Tbilisi, Georgia, but it malfunctions and does not detonate.