Commissioned by President Thomas Jefferson, the Corps' objectives were scientific and commercial – to study the area's plants, animal life, and geography, and to learn how the Louisiana Purchase could be exploited economically.

The foundations for the Corps of Discovery were laid when Thomas Jefferson met John Ledyard to discuss a proposed expedition to the Pacific Northwest in the 1780s.

In 1803, President Thomas Jefferson commissioned the Corps of Discovery, and named as its leader his personal secretary and U.S. Army Captain, Meriwether Lewis, who selected William Clark as his partner.

[7] The goals of the Corps of Discovery, whose cadre would be raised primarily from the U.S. military, was to explore the Louisiana Purchase, and establish trade and U.S. sovereignty over the native peoples along the Missouri River.

Jefferson also wanted to establish a U.S. claim to the Pacific Northwest and Oregon territory by documenting an American presence there before other European nations could lay title to the land.

[11][12][13][14] To create the Corps of Discovery, and to ensure any chance of success, Lewis wanted to find the best possible men he could and recruit them to join his expedition.

They would be among a select group of white people to see the area abounding with elk, deer, bison, and beavers before the large-scale encroachment of European Americans.

Some researchers assert that without such contact or help, the Corps of Discovery would have undoubtedly starved to death or become hopelessly lost in the Rocky Mountains.