Who led the Lewis and Clark Expedition?

The Lewis and Clark Expedition, formally called the Corps of Discovery, was led by Captain Meriwether Lewis and Second Lieutenant William Clark, two Virginia-born army officers selected by President Thomas Jefferson to explore the newly acquired Louisiana Territory and chart a route to the Pacific Ocean. Meriwether Lewis was born on August 18, 1774 near Charlottesville, Virginia, served in the militia during the Whiskey Rebellion of 1794, and rose to captain in the regular army. Jefferson hired him in 1801 as private secretary, an unusual personal arrangement that gave Lewis access to the President's library at Monticello and exposure to the latest natural science. Lewis then prepared for the expedition by studying medicine with Dr. Benjamin Rush of Philadelphia, navigation with Andrew Ellicott, botany with Benjamin Smith Barton, and other natural sciences with leading American experts.

William Clark was born on August 1, 1770 in Caroline County, Virginia, the younger brother of Revolutionary War general George Rogers Clark. He served as an army officer on the Ohio frontier from 1789 to 1796, gaining experience with Native nations, river travel, and surveying. Lewis chose Clark as co-commander in 1803 and they shared command equally despite Clark's nominal subordinate rank, addressing each other as Captain throughout.

The expedition assembled at Camp Dubois near St. Louis during the winter of 1803 to 1804 and departed up the Missouri River on May 14, 1804 with about 33 permanent members. The Corps wintered at Fort Mandan in present-day North Dakota in 1804 to 1805, where they hired French-Canadian fur trader Toussaint Charbonneau and his young Shoshone wife Sacagawea, who had been kidnapped from her Lemhi Shoshone band years earlier. Sacagawea, then about 17 and pregnant with her first child, gave birth to Jean Baptiste at the fort on February 11, 1805. She traveled with the expedition through the spring and summer of 1805, served as interpreter when the Corps reached her own people, and helped acquire the horses needed to cross the Bitterroot Mountains.

The party reached the Pacific Ocean at the mouth of the Columbia River on November 7, 1805, wintered at Fort Clatsop in present-day Oregon, and returned to St. Louis on September 23, 1806. They had traveled approximately 8,000 miles in 28 months, mapped vast new territory, encountered roughly 50 Native nations, recorded 178 plants and 122 animals new to science, and lost only one man (Sergeant Charles Floyd to apparent appendicitis on August 20, 1804). Lewis later served briefly as governor of Louisiana Territory before dying under disputed circumstances on October 11, 1809; Clark became Indian agent and governor of Missouri Territory and lived until 1838.