The Corps of Discovery: The Lewis & Clark Expedition

“As we passed on, it seemed those scenes of visionary enchantment would never have an end.”

—Meriwether Lewis—

It’s 1803, and under the direction of President Thomas Jefferson the United States has acquired the Louisiana Territory from France. The territory—around 828,000 square miles—is sold to the US for $11 million and is comprised of what is now fifteen states and two Canadian provinces, starting from modern-day Louisiana and stretching into southern Canada. In addition to increasing the sovereign land of the United States, one of Jefferson’s primary goals was to find a practical northwest passage in which to institute trade and lay claim to lands in the northwestern region before Great Britain and France. In his words, he wanted to find “the most direct and practical water communication across the continent for the purposes of commerce."

To accomplish this, he commissioned an expedition to investigate this possibility, to explore the newly acquired land, and map the western regions for future exploration. These not-so-humble objectives were the foundation for one of the most exciting adventures in American history. The land west of St. Louis was wild, unknown, and virtually uncharted. Beyond the confines of measurable civilization lay an unknown that brought wonder to all would-be explorers. In the modern-day, it’s hard to visualize what it would have been like to take the first step forward into what was then considered the true wild. Two men lead a group that held this honor, Meriwether Lewis and William Clark.


Lewis and Clark came from the US Army. At that time, the entire Army numbered a little over three thousand men, with less than twenty having any experience in engineering. Lewis was serving as Jefferson’s private secretary. He had served as a Captain within the 1st Infantry, and had proved himself to be resourceful, a frontiersman, and leader. Clark was still serving in the Army within the Artillery corps and had engineering experience during his service. Lewis selected Clark, who had been his superior in previous military campaigns in the 1790s. Both men were capable and able to complete the journey, but to prepare Lewis further, Jefferson had him train with doctors for the purposes of medical research, train with astronomers to learn navigation, and improve his skills in geography in order to study maps and other writings from men who had explored parts of the territory – especially the Columbia River – years before.

To begin the selection of men who would accompany them during the journey, Lewis and Clark met in Louisville, Kentucky and what is now Clarksville, Indiana to evaluate volunteers who showed interest in participating in the journey. Men who were brave, unmarried, and healthy were prioritized, and skill sets such as wilderness survival were coveted. It was at these two locations that the “nine young men from Kentucky” were selected, representing the core of the group. After a rigorous selection process, a total of seven officers (five of whom were noncommissioned), thirty enlisted men, and fifteen civilians were selected to be part of the Corps of Discovery. Among this group was Lewis’s slave, York. Training was conducted at Camp Dubois in the Indiana Territory during the spring of 1804 with the group leaving by canoe to meet up with Lewis in St. Charles, Missouri.

Aside from training, massive preparations for food and equipment were made. The Corps was equipped with the most advanced weapons at the time to show military strength, including the .46 caliber Girandoni Air Rifle and repeating arms. In addition to advanced weaponry, the group was also issued flintlock rifles, knives, and tomahawks for close combat. Since the expedition would primarily be done via the Missouri and adjoining rivers, boats were acquired including a 55-foot-long keel boat, a iron-framed vessel to assemble during the journey, and assorted canoes for the party to use. Other supplies included food, medicine, gift packages, and silver friendship medals to help establish peaceful relationship with Indians. The Corps of Discovery departed on May 14th from Camp Dubios, met Louis in St. Charles, and left as full expedition via the Missouri river on May 21, 1804. They passed the last French outpost within a few weeks, and after that, there was only the unknown.

Adventure and Discovery

Over the next several weeks, the group continued west until on August 3rd, they held their first council with Indians in that region. In attendance were members of the Oto and Missouri tribes near what is now Council Bluffs, Iowa. Peace Medals were presented to Indian chiefs during these meetings, and any information that could be interpreted and used about the lands ahead was garnered. Each day, the group traveled farther and farther west, recording the different experiences and schedules in journals while collecting specimens to send back to what was considered the known world.

Throughout the journey upriver, strict discipline was implemented. This included lashes for what is now considered major offenses such as falling asleep on post and drunkenness. Sergeants were positioned on the bow, center, and stern to watch for any possible aggression from the shoreline. At night, boats and supplies were closely guarded. The need for constant security was reinforced early on in the expedition, as previous writings about Native Americans proved irregular, underestimating the military strength of several tribes.

The Great Plains tribe of Lakota (or Sioux) were especially powerful, being cited by Jefferson as “that nation we wish most particularly to make a friendly impression because of their immense power.” When contact was finally made with the chiefs of that nation, the ceremony was a great success both because of the respect showed to the nation and the demonstration of firepower from the state-of-the-art weaponry which brought respect from the tribes in attendance. Later in the voyage, the Corps would encounter another band of Lakota who were known among traders as menacing, but after a show of force the Indians were dissuaded from combat, and even befriended the Corps as a result of what was observed. Among the many attributes seen in the different tribes and Clark encountered, a show of strength had the ability to earn the respect and show the capability of force, both of which lead to no major conflicts during the expedition.

As the fall grew cold and the winter months approached, the Corps of Discovery constructed Fort Mandan to survive the winter. Boats and supplies were brought inside the fort, a new regime was instituted to adapt to the frigid months ahead. Hunting parties were commissioned throughout their stay at the fort, and regular trips were made to find and harvest downed trees for the purposes of firewood collection and repairs to the structure. Visitors from the Lakotas would regularly come to the Fort as well as fur traders who were used to working up and down the river. One of the many visitors was a French-Canadian Fur Trapper named Toussaint Charbonneau and his wife, a Shoshone-born Indian named Sacagawea. Acting as the interpreter, Charbonneau was able to bridge many of the communication gaps between the Lakota and the Corps.

After a long winter, the expedition prepared to leave the Fort on April 7, 1805. At the same time, they dispatched their barge with members of the party back down river. Within the barge was a collection of writings, scientific specimens, and maps about journey thus far. The progress report which constituted most of the writings called, A Statistical View of the Indian Nations Inhabiting the Territory of Louisiana and detailed the various tribes, practices, and water routes the group had encountered thus far. This detailed report was prized by Jefferson, and later presented to Congress. With the barge underway and the party split between those leaving and the “thirty-one men and a woman” continuing, the Corps of Discovery departed Fort Mandan and continued west along the Missouri.

The Missouri began to branch as they traveled, and the Corps moved onto the Yellowstone River. As the party continued west, they passed the great herds of buffalo, elk, and other rich wildlife that up till that point, had never been recorded. According to Lewis, the great herds “were so gentle we pass near them without appearing to excite any alarm, and when we attract their attention they approach more nearly to see what we are." Not long after, the Corps approached the Great Falls of the Missouri and had to travel via land—boats, supplies, and equipment in tow—over hills and through the wilderness while battling exhaustion, heat, and mosquitos. Finally, on July 15 of 1805 they were water-bound again and some days later, Lewis recorded seeing the Rocky Mountains for the first time.

Within the Rocky Mountains lay the Shoshone tribe, the native tribe of their interpreter, Sacagawea. It is recorded that during a forward expedition by Lewis the group encountered a single warrior of that tribe, and that the Chief reported to Lewis that word had spread about their expedition being a ruse by a hostile tribe to institute an ambush. Thankfully, the Chief didn’t believe what was said and began cautious discussions with Lewis. No sooner had the discussions begun than Clark arrived with the rear guard and produced Sacagawea, who was revealed to be the chief’s long-lost sister. Her arrival, testimony, and safe return to her people caused all tensions to subside. As a result, the Shoshone aided the expedition in their resupply, took the declaration of American sovereignty in good spirits, and provided whatever information they could about the journey that lay still in front of the group.

From August to September the Corps of Discovery encountered territory so terrible that one of the members said it was “the most terrible mountains I ever beheld." The Corps continued on through what is now modern-day Idaho and Washington throughout October, encountering rapids, rain, insects and other challenges wrought by the wild. During this time one of the guides informed the group that another tribe downriver were planning an ambush. It is recorded that the news did little to scare the Corps, with the journal entry stating, “Being at all times ready for any attempt of that sort, we were not under greater apprehensions than usual…we therefore only reexamined our arms, and increased the ammunition.”

Finally merging into the Colombia River, they continued west until at last seeing that which was counted as their primary objective, the Pacific Ocean. Using the notes of William Robert Broughton and maps that he had written, the Corps of Discovery oriented themselves with the landmarks provided and used these pieces to help in their navigation. Upon finally seeing the great ocean, it is recorded, “We enjoyed the delightful prospect of that ocean, the object of all our labors, the reward of all our anxieties.” Standing at the mouth of the Columbia River on the shores of a great ocean on November 7, 1805, the Corps of Discovery had traveled over 3,700 miles.

The Trip Home

Immediately after reaching the Pacific, winter quarters had to be established. The Corps voted on where the location would be, and both Sacagawea and York were allowed to participate, making it the first time a woman and African American were allowed to vote in America. They settled on the west side of the Netul River, constructing Fort Clatsop where they remained until March 23, 1806. After some minor skirmishes with the Bitterroot and Blackfeet Indians, the group separated and began to pull from caches they had buried on their journey out to the ocean. Lewis and Clark’s groups rejoined at the mouth of the Yellowstone and Missouri Rivers on August 11th, and with the help of the mighty river, were able to return home on September 23rd to St. Louis writing to President Jefferson, “the corps has penetrated the Continent of North America to the Pacific Ocean.”

Results of the Expedition

As it is with most our episodes, its very difficult to summarize this amazing event in history. The results of the expedition ranged from map-making of the unexplored lands to botany and a detailed account of the different Indian tribes encountered during the journey, all of which held immeasurable value. Lewis and Clark were the first Americans to discover the Continental Divide, experience Yellowstone, cross into Montana and Idaho, and provide maps and details for each place. Though they did not discover a desired “northwest passage”, their dealings with the Indians, negotiations, goodwill, and perceived establishment of American sovereignty secured and claimed title to the explored regions.

The journey of Lewis and Clark marked the beginnings of westward expansion, put on the paper the wild lands of the northwest, and established beneficial relations with Native Americans. The journals and accounts of the expedition have recently been combined and re-released, and I encourage all of you to take some time and read these accounts so that you can experience the moments of discovery with the explorers, first-hand. The Corps of Discovery will forever live on in American history as the ultimate story of adventure into the unknown, bringing the dreams of a fledgling America in its wake as it pushed future expansion, perceived sovereignty, and knowledge of the wild, untamed world.