Lewis and Clark Expedition

Lewis and Clark Expedition (1804–1806).In a January 1803 message to Congress, President Thomas Jefferson called for an expedition up the Missouri River and west to the Pacific. With the Louisiana Purchase later that year, the project took on even greater significance. Jefferson chose the army captain Meriwether Lewis (1774–1809) to lead the expedition. Lewis selected as his partner a fellow officer, William Clark (1770–1838). More than forty men, including York, Clark's slave, composed the Corps of Discovery as it started up the Missouri in a keelboat and three canoes on 14 May 1804. By late October the expedition had reached present‐day central North Dakota, where the members established their winter quarters, Fort Mandan.

In April 1805, Lewis and Clark sent the keelboat downriver before resuming their journey west, accompanied by a young Shoshone woman, Sacagawea (1786–1812), and her French Canadian husband. They reached the source of the Missouri and advanced up a tributary, the Jefferson, before having to abandon their boats. Using horses obtained from Sacagawea's Shoshones, the expedition crossed the Continental Divide at Lemhi Pass and surmounted the Bitterroot Mountains via the Lolo Trail. At the Clearwater River they entrusted their horses to the Nez Percés, built canoes, and floated down the Clearwater, Snake, and Columbia Rivers to the Pacific, which they reached on 18 November 1805. They named their winter quarters Fort Clatsop.

In late March 1806, the corps started home. At the mouth of Lolo Creek the expedition split, Clark's contingent returning as they had come and Lewis's group advancing directly east to the Falls of the Missouri, where the units were reunited. On 23 September 1806, after an absence of twenty‐eight months, the Corps of Discovery arrived at St. Louis.

The Lewis and Clark Expedition, which produced extensive published records and journals, was one of the most successful in the annals of world exploration. It destroyed the concept of an all‐water route to the Pacific and helped fix in the public mind the vast extent of the Louisiana Purchase territory and the Pacific Northwest.
See also Early Republic, Era of the; Expansionism; Indian History and Culture: From 1800 to 1900; Science: Revolutionary War to World War I.

Bibliography

Gary E. Moulton, ed., The Journals of the Lewis and Clark Expedition, 1986–. Stephen E. Ambrose , Undaunted Courage: Meriwether Lewis, Thomas Jefferson, and the Opening of the American West, 1996.

Richard A. Bartlett