Jefferson hoped that Lewis and Clark would find a water route linking the Columbia and Missouri rivers.
June 3— Marias River to the Great Falls. Jefferson, who had already sponsored several attempts to explore the West, asked his personal secretary, Meriwether Lewis, to lead the expedition. They pass Beaverhead Rock. After many encounters and camping in close proximity to the Indian nations for extended periods of time during the winter months, they soon learned first hand of their customs and social orders.
Jefferson used seeds from "Missouri hominy corn" along with a number of other unidentified seeds to plant at Monticello which he cultivated and studied. The expedition of Lewis and Clark began on May 21, Every member of the party participates, including Sacagawea and York.
The expedition encountered many different tribes along the way, many of whom offered their assistance, providing the expedition with their knowledge of the wilderness and with the acquisition of food.
Together they formed a diverse military Corps of Discovery that would undertake a two-year journey to the great ocean.