Meriwether Lewis and William Clark led the Corps of Discovery Expedition across the Louisiana Purchase, a journey connected with the America250-era story of westward exploration.
President Thomas Jefferson commissioned the expedition in 1803, and it departed from near St. Louis in May 1804. The party traveled up the Missouri River, crossed the Rocky Mountains, and reached the Pacific Ocean near present-day Oregon and Washington in November 1805.
The expedition returned to St. Louis in September 1806. Sacagawea, a Lemhi Shoshone woman, traveled with the group for much of the journey and helped with communication and diplomacy. The expedition mapped routes and recorded plants, animals, and geography, but it did not discover an uninhabited wilderness; Indigenous nations already lived throughout the region.