Lewis and Clark Expedition

Historical convention of long standing has it that the expedition of Meriwether Lewis and William Clark was dispatched by President Thomas Jefferson in 1804 to explore the newly acquired territory of Louisiana. In fact, the exploration of Louisiana was a secondary part of the mission of Lewis and Clark. Their primary objective, made clear by Jefferson in a number of letters and other documents, was to locate a commercially practical water route across the North American continent. In other words, Lewis and Clark were sent to find the fabled Northwest Passage. That their expedition (1804–1806) coincided with America's acquisition of the vast territory of Louisiana—the entire western portion of the Mississippi's drainage basin—was simply fortuitous (see Figure 1).

By the time Jefferson was elected president in ...