Lewis and Clark Expedition


When Thomas Jefferson became president of the United States, he was determined to fulfill one of his most cherished dreams: obtaining accurate knowledge of the Far West. In his message to Congress of January 18, 1803, nine months before the United States acquired the Louisiana Purchase from France, Jefferson requested funds to outfit an expedition for the purposes of gathering scientific and geographic information about the trans-Mississippi West and for establishing diplomatic and commercial relations with the Indians of the region.

Jefferson, like other Americans of his era, was also interested in determining whether or not there was a viable water route across the continent that connected with the Pacific Ocean.

With the approval of Congress in hand, Jefferson secured the services of Meriwether Lewis and William Clark. Both men were experienced army veterans and seasoned frontiersmen. They assembled a well-trained Corps of Discovery, one of whom was Clark’s African-American slave, York.


With wilderness gear, boats, and scientific equipment, they began their journey by ascending the Missouri River from the vicinity of St. Louis on May 14, 1804.

The party wintered with the Mandan Indians in proximity to the Knife and Missouri Rivers in what is now the state of North Dakota. There, Lewis and Clark obtained the services of Toussaint Charbonneau, a French-Canadian trapper, and Sacagawea, his young Shoshone wife.

Since both spoke Shoshone and had some knowledge of the Hidatsa language, they were invaluable as interpreters and intermediaries between the Corps and the Indians.

By the following spring, the expedition had reached the three forks of the Missouri, which they named the Jefferson, the Gallatin, and the Madison. After a perilous trek across the Rocky Mountains, they descended the Snake and Columbia Rivers and reached the shores of the Pacific Ocean in November 1805. The expedition erected Fort Clatsop and remained there until spring.

Returning over much of their original route, they arrived at St. Louis on September 23, 1806. The party had traversed some 8,000 miles and had journeyed for well over two years. The hardships they had endured were largely due to the nature of the terrain they traversed, weather conditions, physical and mental fatigue, encounters with wild animals, and accidents.

With the exception of the Blackfeet and the Sioux, their relations with Indians were relatively peaceful and beneficial. They returned with a wealth of information about the Indians and the topography of the Far West.

The knowledge they gathered about the flora and fauna of the region proved to be invaluable for the traders, trappers, and settlers who followed. Their explorations also helped to affirm the right of the United States to Oregon Country.

The journals of Lewis and Clark have been published in many editions. They offer vivid descriptions of the explorers’s encounters with the unexpected and relate their struggles with their day-to-day routines. The journals constitute an American saga.