What was the name of the 1804–1806 U.S. expedition led by Meriwether Lewis and William Clark?

The Lewis and Clark Expedition was the 1804–1806 U.S. expedition led by Meriwether Lewis and William Clark.

President Thomas Jefferson commissioned the expedition after the United States acquired the Louisiana Territory in 1803. Its instructions included exploring the newly acquired lands, mapping routes, studying plants and animals, and seeking a practical water route across the continent.

The expedition’s Corps of Discovery departed from Camp Dubois in Illinois on May 14, 1804. The party traveled up the Missouri River, crossed the Rocky Mountains, and reached the Pacific Ocean before returning east. Sacagawea accompanied the group with her infant son and assisted with translation and diplomacy, while York, an enslaved man owned by Clark, also traveled with the expedition.

The expedition is often described as the first American overland expedition to cross the territory that became the western United States. It did not “discover” an empty land: many Indigenous nations already lived throughout the region and provided essential knowledge, supplies, and assistance.