Lewis and Clark Depart

Setting the scene

The Lewis and Clark Expedition, officially the Corps of Discovery, departed Camp Dubois near St. Louis on May 14, 1804, to explore the Louisiana Purchase. President Thomas Jefferson had purchased Louisiana from France in 1803 for $15 million, doubling the nation's size, but knew little about the territory. He commissioned his private secretary, Meriwether Lewis, to lead an expedition to find a water route to the Pacific, document natural resources, and establish relations with Native American tribes. Lewis chose William Clark as co-leader.

What happened

The expedition of about 45 men, including soldiers, interpreters, and Clark's enslaved man York, traveled up the Missouri River in a keelboat and pirogues. They wintered at Fort Mandan in North Dakota (1804-1805), where they met Sacagawea, a Shoshone woman who, with her French-Canadian husband Toussaint Charbonneau, joined as interpreter and guide. In 1805, they crossed the Rocky Mountains, descended the Columbia River, and reached the Pacific Ocean on November 15, 1805, wintering at Fort Clatsop in Oregon.

Why it still matters

The expedition returned to St. Louis on September 23, 1806, having traveled 8,000 miles. They mapped the route, documented 178 plants and 122 animals new to science, and established relations with dozens of tribes. Their journals provided the first detailed American knowledge of the West. The expedition fulfilled Jefferson's vision of an 'empire of liberty' spanning the continent and opened the West to American expansion, with devastating consequences for Native peoples. Lewis and Clark became American heroes, embodying the spirit of exploration and manifest destiny that would drive 19th-century expansion.

Background

It gathered knowledge of peoples and terrain.