Portrait of Captain Meriwether Lewis.

Jefferson selected as leader for the exploring mission an Army captain, 28-year-old Meriwether Lewis. The Jeffersons and Lewises had been neighbors near Charlottesville, Virginia, where Lewis was born August 18, 1774. As a boy he had spent long hours tramping and hunting in the woods and acquiring a remarkable knowledge of native plants and animals. He served in the Virginia Militia when President Washington called it out in 1794 to quell the Whiskey Rebellion. Lewis was having a successful career in the regular army when the newly elected Jefferson summoned him in 1801 to work as his private secretary in the "President's House."

In preparing for the expedition, Lewis visited the president's scientific friends in Philadelphia for instruction in natural sciences, astronomical navigation and field medicine. He also was given a long list of questions to ask of western Indians concerning their daily lives. It was during these organizing endeavors that Lewis, for "20$" purchased Seaman, his "dogg of the newfoundland breed" to accompany him to the Pacific.

On September 23, 1806, the tattered Corps of Discovery arrived at St. Louis and "received a harty welcom from it's inhabitants." It had been a great expedition. Jefferson's explorers had covered 8,000 miles of territory over a period of 2 years, 4 months, and 9 days. Its records contributed important new information concerning the land, its natural resources, and its native peoples. Lewis and Clark learned that the surprising width of the Rocky Mountain chain effectively destroyed Jefferson's hoped-for easy connection between the Missouri and Columbia river systems. This finding was the expedition's single most important geographical discovery, resulting in a route over South Pass (Wyoming) during later follow-up trips westward by fur traders and other explorers. There had been plenty of difficulties, but Lewis and Clark were as firm friends as when they started. Congress rewarded the officers and men of the military enterprise, including Toussaint Charbonneau, with grants of land. Sacagawea received no compensation for her services.

On February 28, 1807, President Jefferson picked Lewis to be Governor of Upper Louisiana Territory. His career started well, but controversy involving government finances arose in 1809 culminating with his decision to travel to Washington, D.C., to resolve the dispute. Traveling through Tennessee, Governor Meriwether Lewis on October 11, 1809, died mysteriously from gunshot wounds inflicted while at Grinder's Stand, a public roadhouse. It is not known conclusively whether he was murdered or committed suicide. His grave lies where he died, within today's Natchez Trace National Parkway near Hohenwald, Tennessee.