Lewis and Clark

The 1804–1806 expedition, and what it was actually for.

The Corps of Discovery, led by Meriwether Lewis and William Clark, travelled from St Louis to the Pacific and back between 1804 and 1806. It followed the Louisiana Purchase, in which the United States bought French claims to a vast territory — claims that took no account of the nations already living there.

Objectives

Jefferson's instructions were explicit: find a practical water route across the continent for commerce; record plants, animals, minerals and terrain; and establish relations with Native nations, partly to redirect the fur trade away from the British. The hoped-for Northwest Passage did not exist, and establishing that was itself a result.

Findings

The expedition documented roughly 178 plants and 122 animals new to American science, produced the first reasonably accurate maps of the region, and recorded detailed observations of dozens of Native nations. The journals are the primary source and remain extensively studied.

Who made it possible

Sacagawea, a Lemhi Shoshone woman, joined with her husband Toussaint Charbonneau and travelled the route carrying an infant. She interpreted, identified edible plants, and — because a war party would not travel with a woman and baby — her presence signalled peaceful intent. Her reunion with her brother, a Shoshone chief, secured the horses needed to cross the Rockies.

York, an enslaved man owned by Clark, made the entire journey and worked as a full member of the party. He was not freed on return, and his later life is poorly documented. The expedition also depended repeatedly on food, guidance and shelter from Native nations along the route.

Consequences

The expedition opened the region to American settlement and the fur trade, and the displacement, treaty violation and violence that followed for the nations who had made it possible. Accounts that treat it purely as an adventure story omit half of what it set in motion.