born Aug. 18, 1774, near Charlottesville, Va.
died Oct. 11, 1809, near Nashville, Tenn., U.S.
U.S. explorer.
After serving in the militia during the Whiskey Rebellion (1794) in western Pennsylvania, he transferred into the regular army. In 1801 he became private secretary to Pres. Louisiana Purchase . At Lewis's request, William Clark was appointed to share the command. The success of the {{link=Lewis and Clark Expedition">Lewis and Clark Expedition (1804–06) was greatly due to Lewis's preparation and skill. At its conclusion, he and Clark each received 1,600 acres of land as a reward. Lewis was named governor of Louisiana Territory in 1808. He died under mysterious circumstances in an inn on the Natchez Trace while en route to Washington; whether his death resulted from murder or suicide is still a subject of controversy.