He explored and mapped the American Northwest with his partner William Clark.
He was appointed to be President Thomas Jefferson's aide in 1801 and provided him with information regarding army politics.
In addition to helping to map the U.S., he served as governor of Louisiana.
He was the son of Lt. William Lewis and Lucy Meriweather. His father died of pneumonia when he was a child.
Napoleon Bonaparte sold the U.S. a large amount of land in what came to be known as the Louisiana Purchase. Lewis and Clark set out explore this land.