Which 1804–1806 expedition explored lands acquired through the Louisiana Purchase?

The Lewis and Clark Expedition explored lands acquired through the Louisiana Purchase from 1804 to 1806.

President Thomas Jefferson commissioned Meriwether Lewis and William Clark to investigate the new territory, map routes, study plants and animals, and seek a practical route to the Pacific Ocean. The expedition began near St. Louis in May 1804 and reached the Pacific coast in November 1805 before returning in September 1806.

The Corps of Discovery relied heavily on assistance from Native nations. Sacagawea traveled with the party and helped communicate and navigate, while her presence also signaled peaceful intentions to some communities. The expedition’s success expanded American geographic knowledge, though it did not mean the land was unoccupied or freely available.

The expedition is often described as a simple coast-to-coast trek, but it was a complex scientific, diplomatic, and military project. It did not discover the Pacific Northwest for Europeans or Native peoples; rather, it surveyed areas unfamiliar to the United States government.