Who co-led the Lewis and Clark Expedition with William Clark?

Meriwether Lewis co-led the Lewis and Clark Expedition with William Clark. President Thomas Jefferson appointed Lewis to command the expedition, and Lewis invited Clark to share leadership.

The expedition began near St. Louis in May 1804 and traveled up the Missouri River, across the Rocky Mountains, and down the Columbia River to the Pacific coast. The Corps of Discovery returned to St. Louis in September 1806 after covering thousands of miles.

Its goals included finding a practical route across the continent, mapping territory, studying plants and animals, and establishing U.S. diplomatic and commercial relationships with Native nations. The explorers relied on help from many Indigenous people, including Sacagawea, whose knowledge and interpreting assistance supported the journey.

The expedition did not travel through an uninhabited wilderness. It crossed lands occupied by numerous Indigenous nations, and later U.S. expansion brought displacement and conflict. Lewis and Clark’s maps and reports nevertheless influenced American geographic knowledge and westward policy.