The Lewis and Clark Expedition (1804–1806), was the first transcontinental
expedition to the Pacific coast undertaken by the United States. Commissioned
by President Thomas Jefferson, it was led by two Virginia-born veterans of Indian
wars in the Ohio Valley, Meriwether Lewis and William Clark. Their objectives were
both scientific and commercial, to study the area’s plants, animal life, and geography,
and to learn how the region could be exploited economically.