Meriwether Lewis to Thomas Jefferson, 1805

Captain Meriwether Lewis wrote this letter to President Thomas Jefferson in early April 1805 from Fort Mandan, near present-day Washburn, North Dakota. It was hand-copied and the spelling corrected in about 1901 by one of Lewis’s relatives for Eva Emery Dye, a writer in Oregon City who was doing research on the Lewis and Clark Expedition.

Lewis begins his letter to the president with a description of the scientific samples he was sending, along with a map of the country the Corps had already traversed. Lewis hoped that information about the geography and natural history of the Missouri River country would be of value to the scientific community.

Lewis also noted that he had forwarded to the U.S. Secretary of War “every information relative to the geography of the country which we possess, together with a view of the indian nations.” In 1803, President Jefferson had arranged to “purchase” from the French 827,000 square miles of land that Americans and Europeans called Louisiana. In order to exert American political dominance over the vast region, the U.S. government needed information about the area’s physical and cultural geography. A key mission of the Corps of Discovery was to gather that information, as well as to announce the United States’ territorial claims and to begin establishing American control over the Missouri River trade system.

Finding the most economical route to the Pacific Ocean was another important goal, one meant to increase the commercial power of the United States relative to Europe. In his letter to the president, Lewis describes how the Corps intended to cross the Rocky Mountains and proceed down the Columbia River to the Pacific Ocean. The arduous journey took them longer than Lewis anticipated, however, and the Corps ended up wintering at Fort Clatsop near the mouth of the Columbia. Nevertheless, Lewis managed to meet with the president before the end of 1806, only a couple months after the September 1806 date he told Jefferson to expect him in Virginia.

Written by Cain Allen,  2004; revised 2021

Further Reading

Ambrose, Stephen E. Undaunted Courage: Meriwether Lewis, Thomas Jefferson, and the Opening of the American West. New York: Simon and Schuster, 1996.

Ronda, James R. Lewis and Clark Among the Indians. Lincoln. Lincoln: University of Nebraska Press, 1984.