Lewis and Clark State Historic Site

One Lewis and Clark Trail
Hartford, IL 62048



The Illinois Starting Point of the Lewis & Clark Expedition
On January 18, 1803, President Thomas Jefferson proposed the first official government expedition to explore the vast unknown lands west of the Mississippi River. Jefferson's plan was outlined in a secret message to Congress. He proposed an expedition across the continent to the Pacific Ocean, stressing the importance of discovering commercial opportunity. But it would discover much more.

The Mission to Explore the Continent
Jefferson selected Meriwether Lewis, a captain in the U.S. Army, to lead the expedition, entrusting to him responsibility to find "the most direct & practicable water communication across this continent for the purposes of commerce." The members of the expedition were also to document the territory and to make contact with the native peoples living there. Jefferson believed that a successful expedition might further American trade and political influence and advance American interests in its competition with France, England and Spain. Lewis's commission papers included many pages of specific, task-oriented instructions, a letter of unlimited U.S. credit, and British and French passports. With Jefferson's approval, Lewis invited William Clark to be co-commander of the expedition, and gave Clark the rank of captain.

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