Meriwether Lewis

Meriwether Lewis was 29 years old and President Thomas Jefferson's personal secretary when Jefferson handed him an assignment with almost no precedent: cross an unmapped continent, find a water route to the Pacific, and catalog everything along the way. Lewis chose William Clark as his co-captain, and together they led the Corps of Discovery out of St. Louis in May 1804. Over the next two and a half years the expedition traveled roughly 8,000 miles through territory no American had charted, depending at crucial moments on Shoshone guide Sacagawea and on Native nations whose cooperation the party could not have survived without.

The expedition returned in September 1806 to a nation that treated both captains as heroes, and Jefferson rewarded Lewis with the governorship of Louisiana Territory, based in St. Louis. The job suited his exploring skills far less than his wilderness instincts had. Lewis struggled with the territory's tangled land claims and political factions, fell behind on the official journals he had promised to publish, and ran up personal debts that Washington was slow to repay. Friends and biographers alike describe a man increasingly withdrawn, drinking heavily, and prone to the depressive spells that may have run in his family.

On October 11, 1809, Lewis died of gunshot wounds at a remote Tennessee inn on the Natchez Trace, 35 years old. Most historians, including Jefferson himself, concluded he had taken his own life; a minority have argued for murder by robbers or an innkeeper's household, and the case has never been conclusively settled either way. His expedition journals, delayed for years, were not published in full until 1904.