The Lewis and Clark Expedition was also termed the Corps of Discovery afterwards, a name that acknowledges the group of people who cooperated in travelling together, to reach their destination and return. The Corps of Discovery, made up of thirty to forty men and one woman, was led by Captain Meriwether Lewis and William Clark from St. Louis to the Pacific Ocean and back in 1804-06.

The Corps of Discovery was a group of military men on a scientific expedition. President Thomas Jefferson selected Captain Lewis to lead the expedition, and gave him the mission to explore the Missouri River, and find a river route to the Pacific Ocean.

They were also instructed to study and document the geography, geology, plants and animals, Native cultures and languages, possibilities for settlement, as well as the extent of British and French Canadians hunters, within the vast area they journeyed through.

The Corps of Discovery travelled west on the Missouri River, crossed the Continental Divide, and descended in canoes on the Clearwater, Snake, and Columbia Rivers to the Pacific Ocean. They were successful in the sense that they not only returned alive (with the exception of one member), but also brought back volumes documenting their observations and study, including maps and drawings, plus collections of Native cultural artifacts, plant specimens and animal specimens.