The Corps of Discovery

For nearly two decades at the end of the 18th century, Thomas Jefferson dreamed of mounting an expedition to explore the virtually unknown North American continent west of the Mississippi River. Like others of his era, Jefferson believed in the existence of the Northwest Passage, a navigable route between the northern Pacific and Atlantic Oceans, the discovery of which could revolutionize trade between the United States and the Orient and speed the growth (and increase the wealth) of the young republic.

In January 1803, President Jefferson finally succeeded in securing funding from Congress to outfit such an ambitious undertaking. Congress granted $2,500, though the eventual cost would top $38,000.

Jefferson invited his secretary, 28-year-old Meriwether Lewis, to lead the expedition, which the president named the Corps of Discovery. Its stated goals would be “to make friends and allies of the far Western Indians while at the same time diverting valuable pelts from the rugged northern routes used by [Great Britain]…and bringing the harvest down the Missouri to the Mississippi and thence eastward by a variety of routes.”

Furthermore, Lewis would be charged with mapping the territory and chronicling the people, plants, and animals encountered along the way. Lewis, in turn, asked a former Army comrade, William Clark, to cocaptain the expedition with him.

Just two months after Congress approved the request, Jefferson consummated the Louisiana Purchase, an agreement that ceded New Orleans and 820,000 square miles of France’s North American territories to the United States, for $15 million — about three cents per acre. Overnight, the area of the United States doubled, and Lewis and Clark’s mission assumed even greater importance.

In May 1804, after months of preparation and recruitment, the Corps set off in a large keelboat and two pirogues up the Missouri River from a base near St. Louis [1], then the western edge of white civilization. Over the next two years, their route would take them north and west, up the drainages of the Missouri River, across the Rockies, into the Columbia River system, and finally to the Pacific Ocean. The Corps, consisting of 32 men and one woman, the Shoshone Sacagawea, would spend October 1805 to May 1806 in what are today Oregon [2] and Washington [3], including four wet, miserable months at Fort Clatsop near Astoria [4].

Along the way, Lewis and Clark charted some 8,000 miles of territory hitherto unexplored by European Americans and documented 300 species of flora and fauna previously unknown to Western science. Journals kept by Lewis, Clark, and three of their sergeants chronicle their experiences with such vividness that they still captivate readers today. The effect their journey had in accelerating westward expansion of the United States across the continent can hardly be overstated.