The Lewis and Clark Expedition, also known as the Corps of Discovery Expedition, was the United States expedition to cross the newly acquired western portion of the country after the Louisiana Purchase. The Corps of Discovery was a select group of U.S. Army and civilian volunteers under the command of Captain Meriwether Lewis and his close friend Second Lieutenant William Clark. Clark, along with 30 others, set out from Camp Dubois (Camp Wood), Illinois, on May 14, 1804, met Lewis and ten other members of the group in St. Charles, Missouri, then went up the Missouri River. The expedition crossed the Continental Divide of the Americas near the Lemhi Pass, eventually coming to the Columbia River, and the Pacific Ocean in 1805. The return voyage began on March 23, 1806, at Fort Clatsop, Oregon, ending six months later on September 23.
President Thomas Jefferson commissioned the expedition, shortly after the Louisiana Purchase of 1803, to explore and detail as much of the new territory as possible. Furthermore, he wished to find a practical travel route across the western half of the continent—directly avoiding the hot and desolate desert southwest—and to establish an American presence in the new lands before European powers attempted to establish claims of their own. The campaign's secondary objectives were scientific, economical and humanitarian, i.e., to document the West's biodiversity, topography and geography and to establish positive trade relations with (potentially unknown) Native American tribes. The expedition returned to St. Louis to report their findings to President Jefferson via maps, sketches, and various journals.
Motivations
One of Thomas Jefferson's goals was to find "the most direct and practicable water communication across this continent, for the purposes of commerce". He also attached special importance to declaring US sovereignty over the land inhabited by the many different Native American tribes along the Missouri River, and to securing an accurate sense of the resources in the recently completed Louisiana Purchase. The expedition made notable contributions to science, but scientific research was not the main goal of the mission.
Preparations
For years, Thomas Jefferson read accounts about the adventures of various explorers on the western frontier, and, consequently, maintained a long-held interest in further exploring this mostly-unknown region of the continent. In the 1780s, while Minister to France, Jefferson met John Ledyard in Paris, where they discussed a possible trip to the Pacific Northwest. Jefferson had also read Captain James Cook's A Voyage to the Pacific Ocean (London, 1784), an account of Cook's third voyage, and Le Page du Pratz's The History of Louisiana (London, 1763), all of which greatly influenced his decision to send an expedition. Like Captain Cook, he wished to discover a practical route through the Northwest to the Pacific coast. Alexander Mackenzie had already charted a route in his quest for the Pacific, following Canada's Mackenzie River to the Arctic Ocean in 1789. Mackenzie and his party were the first non-indigenous people to cross mainland North America, north of Mexico, reaching the Pacific coast of British Columbia in 1793–twelve years earlier than Lewis and Clark. Mackenzie's accounts in Voyages from Montreal (1801) informed Jefferson of Britain's intent to establish control over the lucrative fur trade of the Columbia River, convincing him of the importance of securing the territory posthaste. In Philadelphia, Israel Whelen, purveyor of public supplies, purchased necessities for the expedition with a list provided by Lewis; among the items found were 193 pounds of portable soup, 130 rolls of pigtail tobacco, 30 gallons of strong spirit of wine, a wide assortment of Native American presents, medical and surgical supplies, mosquito netting, and oilskin bags.
Two years into his presidency, Jefferson asked Congress to fund an expedition through the Louisiana territory to the Pacific Ocean. He did not attempt to make a secret of the Lewis and Clark expedition from Spanish, French, and British officials, but rather claimed different reasons for the venture; he used a secret message to ask for funding, due to poor relations with the opposition Federalist Party in Congress. Congress subsequently appropriated $2,324 for supplies and food, the appropriation of which was left in Lewis's charge.
In 1803, Jefferson commissioned the Corps of Discovery and named Army Captain Meriwether Lewis its leader, who then invited William Clark to co-lead the expedition with him. Lewis demonstrated remarkable skills and potential as a frontiersman, and Jefferson made efforts to prepare him for the long journey ahead as the expedition was gaining approval and funding. Jefferson explained his choice of Lewis:
It was impossible to find a character who to a complete science in botany, natural history, mineralogy & astronomy, joined the firmness of constitution & character, prudence, habits adapted to the woods & a familiarity with the Indian manners and character, requisite for this undertaking. All the latter qualifications Capt. Lewis has.
In 1803, Jefferson sent Lewis to Philadelphia to study medicinal cures under Benjamin Rush, a physician and former leader in the American Revolution. He also arranged for Lewis to be further educated by Andrew Ellicott, an astronomer who instructed him in the use of a sextant, among other navigational instruments. From Benjamin Smith Barton, Lewis learned how to describe and preserve plant and animal specimens; from Robert Patterson, refinements in computing latitude and longitude, and Caspar Wistar covered fossils, and the search for possible living remnants. Lewis, however, was not ignorant of science, having demonstrated a marked capacity to learn, especially with Jefferson as his teacher. At Monticello, Jefferson possessed an enormous library on the subject of North American geography, to which Lewis had full access. He spent time consulting maps and books, as well as conferring with Jefferson.
The keelboat used for the first year of the journey was built near Pittsburgh, Pennsylvania, in the summer of 1803, to Lewis's specifications, and was completed on August 31. The vessel was immediately loaded with equipment and provisions. While in Pittsburgh, Lewis bought a Newfoundland dog, Seaman, to accompany them. Newfoundlands are amicable, large working dogs and good swimmers, lovers of water and commonly found on fishing boats, as they can assist in water rescues. Seaman proved a valuable member of the party, aiding with hunting and protection from bears and other potential predators. He was the only animal to complete the entire trip.
Lewis and his crew set-sail that afternoon, traveling down the Ohio River to meet up with Clark near Louisville, Kentucky, in October 1803, at the Falls of the Ohio. Their goals were to explore the vast territory acquired by the Louisiana Purchase and to establish trade and US sovereignty over the Native Americans along the Missouri River. Jefferson also wanted to establish a US claim of "discovery" to the Pacific Northwest and Oregon Territory by documenting an American presence there before European nations could claim the land. According to some historians, Jefferson understood that he would have a better claim of ownership to the Pacific Northwest if the team gathered scientific data on animals and plants. However, his main objectives were centered on finding an all-water route to the Pacific coast and commerce. His instructions to the expedition stated:
The object of your mission is to explore the Missouri River, & such principle stream of it, as, by its course and communication with the waters of the Pacific ocean, whether the Columbia, Oregon, Colorado or any other river may offer the most direct & practicable water communication across this continent for the purpose of commerce.
The US mint prepared special silver medals with a portrait of Jefferson and inscribed with a message of friendship and peace, called Indian Peace Medals. The soldiers were to distribute them to the tribes that they met. The expedition also prepared advanced weapons to display their military firepower. Among these was an Austrian-made .46 caliber Girandoni air rifle, a repeating rifle with a 20-round tubular magazine that was powerful enough to kill a deer. The expedition was prepared with flintlock firearms, knives, blacksmithing supplies, and cartography equipment. They also carried flags, gift bundles, medicine, and other items that they would need for their journey.
The route of Lewis and Clark's expedition took them up the Missouri River to its headwaters, then on to the Pacific Ocean via the Columbia River, and it may have been influenced by the purported transcontinental journey of Moncacht-Apé by the same route about a century before. Jefferson had a copy of Le Page's book in his library detailing Moncacht-Apé's itinerary, and Lewis carried a copy with him during the expedition. Le Page's description of Moncacht-Apé's route across the continent neglects to mention the need to cross the Rocky Mountains, and it might be the source of Lewis and Clark's mistaken belief that they could easily carry boats from the Missouri's headwaters to the westward-flowing Columbia.
Journey
Departure
The Corps of Discovery departed from Camp Dubois (Camp Wood) at 4 pm on May 14, 1804. Under Clark's command, they traveled up the Missouri River in their keelboat and two pirogues to St. Charles, Missouri, where Lewis joined them six days later. The expedition set out the next afternoon, May 21. While accounts vary, it is believed the Corps had as many as 45 members, including the officers, enlisted military personnel, civilian volunteers, and York, an African-American man enslaved by Clark.
From St. Charles, the expedition followed the Missouri through what is now Kansas City, Missouri, and Omaha, Nebraska. On August 20, 1804, Sergeant Charles Floyd died, apparently from acute appendicitis. He had been among the first to sign up with the Corps of Discovery and was the only member to die during the expedition. He was buried at a bluff by the river, now named after him, in what is now Sioux City, Iowa. His burial site was marked with a cedar post on which was inscribed his name and day of death. 1 mile (2 km) up the river, the expedition camped at a small river which they named Floyd's River. During the final week of August, Lewis and Clark reached the edge of the Great Plains, a place abounding with elk, deer, bison, pronghorn, and beavers.
The Lewis and Clark Expedition established relations with two dozen Native American nations, without whose help the group would have risked starvation during the harsh winters and/or become hopelessly lost in the vast ranges of the Rocky Mountains.
The Americans and the Lakota nation (whom the Americans called Sioux or "Teton-wan Sioux") had problems when they met, and there was a concern the two sides might clash. According to Harry W. Fritz, "All earlier Missouri River travelers had warned of this powerful and aggressive tribe, determined to block free trade on the river. ... The Sioux were also expecting a retaliatory raid from the Omaha tribe, to the south. A recent Sioux raid had killed 75 Omaha men, burned 40 lodges, and taken four dozen prisoners." The expedition held talks with the Lakota near the confluence of the Missouri and Bad rivers in what is now Fort Pierre, South Dakota.
One of their horses disappeared, and they believed the Sioux were responsible. Afterward, the two sides met and there was a disagreement, and the Sioux asked the men to stay or to give more gifts (or tribute) instead, before being allowed to pass through their territory. Clark wrote they were "warlike" and were the "vilest miscreants of the savage race". They came close to blows several times, until the Lakota chief, Black Buffalo, persuaded Lewis to distribute more tobacco to the assembled warriors. Lewis complied and the expedition was allowed to continue upstream to the Arikara villages.
In the winter of 1804–1805, the party built Fort Mandan, near present-day Washburn, North Dakota. Just before departing on April 7, 1805, the expedition sent the keelboat back to St. Louis with a sample of specimens, some never-before-seen east of the Mississippi. One chief asked Lewis and Clark to provide a boat for passage through their national territory. The Americans quickly continued westward (upriver), and camped for the winter in the Mandan nation's territory.
After the expedition had set up camp, nearby tribal members came to visit in fair numbers, with some staying overnight. For several days, Lewis and Clark met in council with Mandan chiefs. Here they met a French-Canadian fur trapper named Toussaint Charbonneau, and his young Shoshone wife, Sacagawea. Charbonneau, at this time, began to serve as the expedition's translator. Peace was established between the expedition and the Mandan chiefs with the sharing of a Mandan ceremonial pipe. By April 25, Captain Lewis wrote his progress report of the expedition's activities and observations of the Native American nations they had encountered to-date in A Statistical view of the Indian nations inhabiting the Territory of Louisiana, which outlined the names of various tribes, their locations, trading practices and water routes used, among other points. President Jefferson would later present this report to Congress.