Victory by the United States in the Revolutionary War didn’t mark the end of its problems with European conquest of North America. As Julie M. Fenster describes in Jefferson’s America, her remarkable history of the exploration of the American frontier, without proper mapping and settlement, the Louisiana Purchase was little more than a few words on paper, the territory ripe to be plucked away, part and parcel, by Spain, France, and England.
“The French,” writes Fenster, “sold Louisiana and intentionally left the detail of drawing boundaries to the new owners.” She later writes that the Spanish, who had a significant military and administrative presence in the western frontier, “had come to the sensible conclusion that without money or soldiers or people in abundance, a territory can’t be controlled. It can only be held, and rather gently … Exploration could assert control, because accurate information was another basis of power.”
The Louisiana Purchase was France’s idea. With the French and British on the cusp of war, Napoleon didn’t dare attempt to hold a North American front in addition to the European theatre. He knew that the British would invade from Canada at the first opportunity. Moreover, France’s grip on its North American holdings was tenuous at best, the U.S. Congress making things worse with its increasing disposition in favor of an armed seizure of New Orleans. The whole continent was just more trouble than it was worth, and so the French government offered to sell its territory for a song.
Jefferson jumped at the opportunity and, as he later wrote, “by a reasonable and peaceable process, we have obtained in 4. months what would have cost us 7. years of war, 100,000 human lives, 100 millions of additional debt.”
For Jefferson, it was about more than territory and political intrigue. While holding the offices of the vice presidency and later the presidency, he also ran the American Philosophical Society, one of the first science institutions in the United States. The frontier presented a bonanza of unknown flora, fauna, ecosystems, and geology, and it was Jefferson’s personal obsession to have the frontier thoroughly mapped and studied.
Such exploration would be no small task either physically or intellectually. In his own words, he sought in his ideal explorer “a person who to courage, prudence, habits & health adapted to the woods, & some familiarity with the Indian character, joins a perfect knowledge of botany, natural history, mineralogy & astronomy.” Though he doubted such men existed in America, a blizzard of correspondence issued by his own hand would turn up a few explorers up to the task. These explorers were sometimes called “Jefferson’s Men,” and they managed the seemingly impossible: the exploration, mapping, and surveying of the west. Here are seven explorers of the American frontier, and how they did it.
MERIWETHER LEWIS AND WILLIAM CLARK
Captain Meriwether Lewis and Lieutenant William Clark were tasked by Jefferson to explore the Louisiana territory and map a route across the western half of North America. They were to satisfy Jefferson’s hopes for information on flora and fauna, and to establish trade with the American Indians they encountered along the way. Moreover, they were to assert American sovereignty over the areas explored—in other words, to let everyone they encountered know that this land was our land. There and back, the expedition lasted just under two-and-a-half years. The journey started out in Wood River, Illinois, and ended at the mouth of the Columbia River in present-day Washington State.
The return trip, which lasted six months, saw the group split so as to more efficiently explore even more territory, which included Yellowstone and the Continental Divide. The expedition ended on September 23, 1806. This expedition is notable for the inclusion of Sacajawea, whose contributions involved some work as a guide, but far more significantly, as a multilingual ambassador to tribes encountered along the way.
WILLIAM DUNBAR AND GEORGE HUNTER
Fenster describes George Hunter as an “animated tourist,” who “delighted in everything from the howl of wolves in the distance to the sight of another vessel on the river.” He was “a good frontiersman and always a resilient one.” He was also a chemist of some repute, which fit Jefferson’s bill for someone able to truly study the land. William Dunbar, meanwhile, was a wealthy trader whose loyalties were ever in motion. Spanish, French, American—it was all the same to him. He just wanted to be out there. He had a love of, and talent for, science, and word of this reached the vice president of the United States and president of the American Philosophical Society. In Fenster’s words, Jefferson “initiated correspondence, capturing Dunbar as though he were a bird formerly believed extinct.”
While Lewis and Clark explored the northern part of the Louisiana Purchase, Dunbar and Hunter, soon brought together, were charged with the Ouachita River, an “alligator-infested, lumber-clogged river in the parched Southwest.” The expedition brought them to the hot springs of Arkansas. Ultimately, the men completed a geologic and zoological study of the land along the river, as well as a chemical analysis of the hot springs.
THOMAS FREEMAN AND PETER CUSTIS
In 1806, Thomas Freeman and Peter Custis embarked on an exploration of the Red River. Freeman was a highly accomplished surveyor who had completed the highly contentious survey of what would be the nation’s capital on the Potomac, and later helped survey the 31st Parallel separating U.S. and Spanish territory in the Southeast. (A present-day map of the United States will reveal a straight line dividing part of Louisiana from Mississippi, and Florida from Alabama. That is the 31st Parallel. His work in D.C. and in establishing the borders of southern states has stood the test of time.) Custis brought to the expedition his expertise as a naturalist and a physician-in-training.
The men traveled from Natchez, Mississippi to present-day New Boston, in northeast Texas. Along the way, they encountered “almost impenetrable Swamps & Lakes for more than 100 miles,” according to Custis. In Texas, they encountered Spanish soldiers who had been tipped off about their expedition, and were made to turn back. Still, the scientific observations gathered from the 600-mile stretch of frontier proved invaluable to Jefferson, who now knew the land to be worthy of settlement. It also established warm relations with native tribes along the way, and the fallout from the Spanish confrontation would force Spain to allow American expeditions along its Red River holdings.
ZEBULON PIKE 
Zebulon Pike first joined the Army at the age of 15, and 12 years later would be placed in charge of an expedition that would cross the Great Plains and the Rocky Mountains. Pike was, according to Fenster, “born supremely, even mythologically, confident in his sense of mission.” The expedition wasn’t an easy one. After crossing present-day Kansas, they arrived at the Rockies in time for winter and with but a single layer of cotton clothing.
“They had no coats,” writes Fenster, “Or even socks.” When trying to make their way and accurately ascertain where they were, Pike led a group of men to a “blue-tinted mountain” where they might look down and survey the terrain. What seemed a one-day hike turned into four, and even then the mountain “now appeared at the distance of 15 or 16 miles from us, and as high again as what we had ascended.” Fenster describes the mountain as having been “apparently on wheels,” seeming always to be those 15 miles away. Pike eventually turned around, the mountain being “the only thing on earth that ever made him give up.”
The ensuing winter was unkind to the explorers, bringing frostbite, illness, near-starvation, and subzero temperatures. Still, his men believed in Pike and his indomitable spirit, and they survived; they eventually reached the Rio Grande in Spanish territory, where they were rescued (and captured) by the Spanish. Pike and his men were brought to Mexico, and later escorted to the Louisiana border at Natchitoches. The blue-tinted mountain was, of course, what is now called Pike’s Peak.
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