I.

Introduction

Lewis and Clark Expedition, first United States overland exploration of the American West and Pacific Northwest, beginning in May 1804 and ending in September 1806. The expedition was commissioned by President Thomas Jefferson and led by army officers Meriwether Lewis and William Clark. The exploration covered a total of about 13,000 km (about 8,000 mi), from a camp outside St. Louis to the Pacific Ocean and back. Like other scholars in his time, Jefferson believed in the existence of a Northwest Passage, or some kind of water connection between the Atlantic and Pacific oceans. The principal goal of the expedition was to locate such a route and survey its potential as a waterway for American westward expansion. Although Lewis and Clark did not find this route, the expedition succeeded in making peaceful contact with Native Americans and uncovering a wealth of knowledge about the peoples, geography, plants, and animals of the western United States.