Timeline of United States history

This is a timeline of United States history, comprising important legal and territorial changes as well as political, social, and economic events in the United States and its predecessor states. To read about the background to these events, see History of the United States.

Some dates before September 14, 1752, when the British government adopted the Gregorian calendar, may be given in the Old Style.

Prior to 6th century

Year Date Event
8500 BC Folsom tools were created.
5500 BC Beginning of the Oshara Tradition.
1600 BC Beginning of Mississippian Culture.[1]
1000 BC Beginning of the Adena Culture.
200 BC End of the Adena Culture.