When Meriwether Lewis, William Clark, and some forty others set off for the trans-Missisippi West on May 14, 1804, they were entering a mythical landscape. Alonso Decalves’s Travels to the Westward or the Unknown Parts of America (1794) imagined utopian communities there. Perhaps the explorers would find descendants of Madoc, a Welsh prince who was said to have come to America in 1170. Mastodons might still roam the plains. Stories were told of a mountain of salt 180 miles long and 45 miles wide.
Thomas Jefferson had long been curious about the trans-Mississippi West. As early as 1783 he had urged William Clark’s older brother, Revolutionary War hero George Rogers Clark, to undertake an expedition to the region and over the next twenty years tried twice more to rouse interest and raise money for such an endeavor. He also assembled the largest library in North America, perhaps the world, about the western regions. Many of his books were secured while he was the minister to France, from July, 1784, to October, 1789. Jefferson’s curiosity is evident in the instructions he issued to Lewis and Clark. They were to study and report on “the soil & face of the country, it’s growth & vegetable productions, especially those not of the U.S.” They were to examine the fauna, “the mineral productions of every kind,” volcanic activity, and climate.
Two concerns above all else, however, impelled the Lewis and Clark expedition. The first was the quest for a Northwest Passage. On April 7, 1805, as the explorers embarked from Fort Mandan, in what is now North Dakota, where they had spent the winter of 1804-1805, Lewis recorded in his journal: “Our vessels consisted of six small canoes, and two large perogues. This little fleet altho’ not quite so rispectable as those of Columbus or Capt. Cook were still viewed by us with as much pleasure as those deservedly famed adventurers ever beheld theirs.”
Lewis thus linked his journey to those of his European predecessors. Like Christopher Columbus, he was seeking a short route to the Orient. Like Captain James Cook, he hoped to find a Northwest Passage through the new continent that Columbus had inadvertently encountered. Locating this route was Jefferson’s primary concern. When Lewis proposed a side trip to Santa Fe before ascending the Missouri River, Jefferson reminded him, “The object of your mission is single, the direct water communication from sea to sea formed by the bed of the Missouri and perhaps the Oregon.”
Faith in the Northwest Passage rested on the best Enlightenment scientific theories and most up-to-date information. Jefferson believed that nature was as symmetrical as the Palladian architecture that informed his designs for his home Monticello and the buildings of the University of Virginia. Hence the Rocky Mountains of the West would resemble the Blue Ridge Mountains of the East; the Missouri and Columbia Rivers (the latter discovered by the American Captain Robert Gray in 1792) would be like the Potomac. These western rivers would be navigable from their sources to their mouths, and if they did not actually converge, they would be within a short portage of one another through gentle mountainous terrain, perhaps requiring as little as half a day to traverse. The best maps in Jefferson’s library confirmed this vision, though none were based on actual exploration.
The Northwest Passage was important for control of the fur trade, contested by Britain, Spain, Russia, and the United States. It was crucial for Jefferson’s vision of agrarian America. In December, 1787, Jefferson wrote to James Madison, “Our governments will remain virtuous for many centuries; as long as they are chiefly agricultural; and this will be as long as there shall be vacant lands in any part of America.” The negotiations that led to the Louisiana Purchase initially involved only the port of New Orleans, which Jefferson recognized as essential for farmers seeking to get their produce to eastern American and European markets. The Northwest Passage would allow easy access to the Orient as well.
(The entire section is 1672 words.)