United States map showing the area included in the Louisiana Purchase.

The Louisiana Purchase

The U.S. Senate approves the Louisiana Purchase that adds more than 800,000 acres of land – including what would become Missouri – to more than double the size of the United States.


May 14, 1804

On this date in history, the Lewis and Clark Expedition—also known as the Voyage of Discovery—sets out across Missouri to explore the lands west of the Mississippi.