The official leader of the epic Lewis and Clark Expedition, Meriwether Lewis has been called "undoubtedly the greatest pathfinder this country has ever known." Lewis was born to a Virginia planter family in 1774. His father, who had been an officer in the American Revolution, died when Lewis was five years old, and for a brief time he lived in Georgia when his mother moved there with her second husband.

After briefly assuming the management of his family's Virginia plantation, Lewis joined the state militia in 1794 to help put down the Whiskey Rebellion in Pennsylvania. He continued his military career as an officer in the regular army, serving on the frontier in Ohio and Tennessee, and rising to the rank of captain by 1801, when he accepted an invitation from President Thomas Jefferson, an old family friend, to serve as his private secretary.

Jefferson seems to have selected Lewis for this post with a view to placing him in charge of an already-contemplated transcontinental expedition. When Jefferson had proposed such an expedition in 1792, Lewis had been among the first volunteers, although his youth and inexperience disqualified him at the time. Now, with his frontier experience, Lewis made a perfect candidate in Jefferson's eyes, and the President soon set out a course of study that would equip him with the scientific skills needed for his journey. Between 1801 and the appropriation of funds for the expedition in 1803, Lewis studied with members of the faculty at the University of Pennsylvania and gathered information about his proposed route.

To accompany him as co-leader of the expedition, Lewis selected William Clark, a fellow Virginian with whom he had served on the frontier in 1795. After Clark had spent several months studying astronomy and map-making, they set out by keelboat in 1803 to Wood River, Illinois, at the confluence of the Missouri and Mississippi rivers. The next spring, they began their journey up the Missouri River and by October had reached the Mandan villages in present-day North Dakota, where they decided to stay for the winter.

Their sojourn with the Mandan quickly made it clear just how much Lewis and Clark would need to rely upon the goodwill of Indian peoples for their success. The Mandans gave them food, military protection, and valuable information about the path ahead. Their most valuable help came in the form of Touissant Charbonneau, a French Canadian whom they hired as an interpreter, and his Shoshone wife Sacagawea, who provided help as a guide and interpreter. Her very presence helped insure good relations with Indian peoples, as Clark noted in his journal: "We find [that she] reconciles all the Indians, as to our friendly intentions -- a woman with a party of men is a token of peace."

In April of 1805 all thirty-three members of the expedition left the Mandan village and started up the Missouri again. They reached the upward limit of the river's navigable stretch four months later. A band of Shoshone led by Sacagawea's brother provided invaluable assistance, primarily horses, as the expedition began to ascend the Rocky Mountains. By late September, they had crossed the Bitterroot Mountains, cold, wet, hungry and exhausted, and were taken in by the Nez Percé. They travelled down the Columbia River basin and reached the Pacific Ocean in November. Their spirits buoyed by success, they stayed the winter on the Pacific Coast and returned to the United States in 1806 over substantially the same route that had brought them West.

The Lewis and Clark expedition was as widely hailed upon its return as it is remembered in our own time, and as its official leader, Meriwether Lewis reaped the benefits of this acclaim. Jefferson appointed him governor of the Louisiana Territory, a post he assumed in 1808. During his brief time in this office, however, Lewis proved himself a poor administrator. He quarreled with the territorial secretary and local leaders, and failed to keep his superiors in Washington informed of his policies and plans.

In September 1809 Lewis set out for the nation's capital to answer complaints about his actions as governor, and on this trip died a violent but mysterious death in a tavern about 70 miles southwest of Nashville, Tennessee. Whether he committed suicide, as Jefferson believed, or was murdered, as his family maintained, remains uncertain even today.