Which two explorers led the U.S. expedition that surveyed the Louisiana Purchase?

Meriwether Lewis and William Clark led the U.S. expedition that surveyed the Louisiana Purchase.

President Thomas Jefferson commissioned the Corps of Discovery Expedition after the United States acquired Louisiana from France in 1803. Lewis served as Jefferson’s private secretary and was chosen to lead the project; Clark, an experienced army officer and surveyor, became his co-leader.

The expedition left near St. Louis in May 1804 and traveled up the Missouri River, across the Rocky Mountains, and toward the Pacific Ocean. It returned to St. Louis in September 1806. The explorers mapped routes, recorded plants and animals, and documented geography for the U.S. government.

Sacagawea, a Lemhi Shoshone woman, joined the expedition with her husband Toussaint Charbonneau and helped the party communicate and travel. Lewis and Clark did not “discover” an empty wilderness: many Indigenous nations already lived across the region, and the expedition depended on Indigenous knowledge, diplomacy, and trade.