The Lewis and Clark Expedition (1804-1806) was a military mission from the US, led by Meriwether Lewis and William Clark. Their main goal was to explore the new western territories gained from the Louisiana Purchase and find a route to the Pacific Ocean. They traveled around 8,000 miles (13,000 km), which was a big move towards expanding the United States westward.
Lewis, Clark, and their crew, known as the Corps of Discovery, kicked off their adventure on May 14, 1804. They navigated up the Missouri River, crossed the Rocky Mountains, and then paddled down the Columbia River to reach the Pacific Ocean. After spending the winter of 1805-06 in what’s now Oregon, they headed back, arriving in St. Louis on September 23, 1806—two years and four months after they first set out. They successfully explored the new western lands and strengthened the US claim to the Oregon Country. Along the way, they created about 140 detailed maps showing important mountains, rivers, and plains. They also discovered 178 types of plants and 122 animal species that were previously unknown to Euro-Americans.
On top of that, the Corps of Discovery met over two dozen Native American tribes, some of whom had never seen white people before. Most of these tribes were friendly and offered crucial help that was key to the expedition’s success. Sacagawea, a young Shoshone woman who joined the team with her husband, served as an interpreter between the explorers and the Native Americans they met. Her presence helped reassure the tribes that the expedition meant no harm. Lewis and Clark learned a lot about the languages and customs of the Native Americans they encountered and brought back many artifacts with them.
Origins & Preparation
President Thomas Jefferson was super intrigued by the American West. Even though he never ventured beyond the Blue Ridge Mountains himself, he imagined it as this huge, wild area where freedom and republican values could flourish, away from the corruption of the growing cities in the East. Like many folks before and after him, Jefferson thought the U.S. was meant to expand westward, creating an ’empire of liberty’ that would eventually cover the whole continent. After the Revolutionary War wrapped up in 1783, Jefferson tried to convince the famous war hero George Rogers Clark to lead a privately funded expedition into the West. Clark turned him down, but Jefferson didn’t let go of his dream of exploring westward.
When he became president in 1801, Jefferson finally had the chance to make this dream happen. By 1802, he started planning the expedition and picked his private secretary, Meriwether Lewis, to head it up. Lewis was a 28-year-old guy from Virginia who had been in the militia during the Whiskey Rebellion back in 1794. He was just as excited about the West as Jefferson was, and even though he didn’t have a ton of formal education, Jefferson believed in him. He described Lewis as brave, sensible, used to the outdoors, and knowledgeable about Native American customs. To get Lewis ready for the leadership role, Jefferson sent him to Philadelphia to study things like astronomy, medicine, mapping, ethnology, botany, and lunar navigation with some top-notch scientists. While he was in Pennsylvania, Lewis also got a Newfoundland dog named Seaman, who would be his loyal buddy throughout the expedition.
At first, Jefferson pitched the expedition as a purely scientific mission to keep France, Spain, and Britain from getting suspicious about his plans for the western lands. But everything changed after the Louisiana Purchase in 1803 when France sold a massive chunk of land—about 828,000 square miles—to the U.S. With this new territory in hand, Jefferson felt free to be more straightforward about his goals. He told Lewis to explore and map out as much of the new land as he could and find a good route across the continent. Jefferson also wanted the expedition to push through to the Pacific Northwest to establish an American presence there before other European countries got too settled in. Plus, he was hoping they’d discover the legendary Northwest Passage that was said to connect the continent to the Pacific. While there were still scientific and cultural goals, claiming the northwest was definitely the top priority.
As the expedition approached, Lewis realized he needed a co-commander with military experience. So, in July 1803, he brought William Clark on board. Clark was a 33-year-old army vet and the younger brother of George Rogers Clark. However, the U.S. Secretary of War turned down Lewis’ request to promote Clark to captain and instead made him a lieutenant, since the army didn’t really do joint leadership. Still, Lewis treated Clark as his equal during the journey and called him ‘captain’ to keep his rank under wraps from the crew. This turned out to be a smart move. Historian Gordon Wood has noted how well their joint command worked out…Lewis and Clark hardly ever fought and mostly saw eye to eye. They really knew how to lift each other up. Clark had experience as a company commander and had explored the Mississippi River, so he was great at managing the crew and was actually better at surveying, map-making, and handling boats than Lewis. While Lewis could be a bit moody and sometimes liked to wander off by himself, Clark was always tough, steady, and dependable. The best part? Both of them were writers! They constantly jotted down their adventures in vivid and sharp detail, capturing everything from plants and animals to people, weather, geography, and all sorts of unique experiences.
So, with Clark on board, Lewis headed to the federal arsenal in Harper’s Ferry, Virginia, to get weapons while Clark went to Kentucky to recruit men for what was now called the Corps of Discovery. By December, they had a team of 45 people, including officers, enlisted men, civilian volunteers, and York, who was an enslaved African American man owned by Clark. They set up Camp Dubois at the mouth of the Missouri River, about 18 miles from St. Louis, where they spent the winter gathering supplies and getting trained up.
The Expedition Begins: May 1804 to February 1805
On May 14, 1804, Clark and 30 members of the Corps of Discovery kicked off their journey from Camp Dubois. They traveled up the Missouri River using two pirogues and a 55-foot keelboat that Lewis designed himself. They met up with Lewis and the rest of the crew near St. Charles, Missouri, before continuing their trek upstream. They made pretty good progress, covering about 10-20 miles (16-32 km) each day by poling and paddling against the current. By July, they reached the mouth of the Platte River, close to what we now call Omaha, Nebraska, where they set up camp at a spot called Council Bluff. On August 3, they had their first encounter with Native Americans when a small group of Oto and Missouri Indians visited them. Lewis welcomed them with gifts and explained that they were now in US territory, saying that the President was like a new father who would protect them and help them out (Wood, 379).
Three weeks later, they arrived at what’s now Sioux City, Iowa, where 22-year-old Sgt. Charles Floyd got sick and sadly passed away from appendicitis. He was buried by a bluff that now carries his name, making him the only member of the Corps to die during the whole expedition. By the end of August, they entered the Great Plains and saw massive herds of bison—thousands of them—as well as animals that Europeans had never seen before, like prairie dogs, grizzly bears, and pronghorn antelope. While in present-day South Dakota, they ran into some unfriendly Lakota Sioux who were wary of their intentions and wouldn’t let them through. Things almost got violent, but Lewis managed to calm everyone down by handing out tobacco to the Sioux warriors, which convinced them to let the expedition continue on their way.
On October 26, 1804, Lewis and Clark’s expedition made it to the five Mandan Indian villages near what we now call Bismarck, North Dakota, which was about 1,600 miles from Camp Dubois. They decided to spend the winter there and built a fortified place called Fort Mandan just downstream from the villages. For the next five months, they hung out there, trading and building relationships with the Mandan and Hidatsa tribes. During their stay, they met a French-Canadian trapper named Toussaint Charbonneau, who agreed to help as an interpreter. His teenage wife, Sacagawea, who was Shoshone, also joined them. She had been taken from her village by the Hidatsa and sold to Charbonneau, who later married her. When she met Lewis and Clark, she was very pregnant, and in February 1805, she gave birth to a baby boy named Jean Baptiste. Lewis and Clark thought having Sacagawea and her baby around would help show any Native Americans they encountered that they were friendly.
Over Rivers & Mountains: April to September 1805
On April 7, 1805, the Corps of Discovery packed up and left their camp. A small crew headed back to St. Louis on a keelboat carrying letters, maps, and some cool stuff for Jefferson, including live magpies and a prairie dog. The rest of the team continued their journey west, navigating the Missouri River in two pirogues and six dugout canoes. Lewis wrote about the experience in his journal:
Even though our little fleet wasn’t as impressive as those of Columbus or Captain Cook, we were just as excited about it as those famous explorers were about theirs; and I bet we were just as worried about keeping everything safe.
The captains got some helpful info from the Mandan and Hidatsa tribes, which made their trek through what’s now North Dakota and Montana a bit easier. By June 2, they hit a fork in the river. After sending out scouting teams to check both paths, they decided to take the southern route. A few days later, they stumbled upon the Great Falls of the Missouri River, which Lewis described as the most amazing sight he’d ever seen. They had to carry their gear around the falls for 18 miles (29 km), which took them three weeks due to rough terrain, frequent hailstorms, and lots of grizzly bears. They wrapped up this tough portage on July 4 and celebrated Independence Day by finishing off their last bit of alcohol.
By the end of July, they reached the Three Forks of the Missouri River, where Sacagawea recognized Beaverhead Rock from her childhood. She told the captains they were close to her home, where the Shoshone lived. Excited to trade for horses, Lewis went ahead with three guys to scout. On August 12, he climbed up Lemhi Pass at the Continental Divide, hoping to see plains with a river flowing west. Instead, he was met with endless mountains—the Rockies. Although he felt a bit down at first, things turned around in mid-August when they ran into a group of Shoshone led by Sacagawea’s brother, Chief Cameahwait. He welcomed the expedition, and they set up camp near the Shoshone village, naming it Camp Fortunate.
The Shoshones hooked the expedition up with some much-needed horses and introduced them to a guide named Old Toby, who was super familiar with the mountains since he had been through them before. Following Old Toby’s guidance, the crew made their way through the Lemhi Pass and into the Bitterroots, part of the Rocky Mountains. This turned out to be the toughest part of their journey. The trail was steep and dangerous, and it often got really cold, dropping below freezing. Their supplies were running low, so the guys had to drink melted snow and even eat their horses. Clark wrote about how he was soaked and freezing all over, saying he was worried his feet would freeze in the thin moccasins he had on. After eleven awful days, they finally made it out of the Bitterroots and onto Weippe Prairie, where the Nez Perce lived.
More Affairs
To the Pacific & Back: October 1805 to September 1806
The captains managed to build a good rapport with the Nez Perce and got their help in making five dugout canoes from pine trees. With the assistance of two Nez Perce guides, they traveled down the Clearwater and Snake Rivers, finally reaching the Columbia River on October 16. They faced some rough rapids but stayed upbeat since they knew the Columbia led to the Pacific Ocean. Then, on November 7, 1805, they caught sight of the ocean, and Clark couldn’t contain his excitement, writing in his journal: “Ocian in view! O! The joy!…Ocian 4142 miles from the Mouth of Missouri R.” (Wood, 380). However, bad weather held them up, and after everyone voted – including Sacagawea and York – they decided to hunker down for the winter. They spent a really cold winter at Fort Clatsop, which is near what we now call Astoria, Oregon.
On March 23, 1806, Lewis and Clark handed over the fort to the chief of the Clatsop Indians and set off for home. They hung out with the Nez Perce for about a month while waiting for the snow to melt before heading back through the Bitterroots on the Lolo Trail. When they came out of the mountains in late June, they split into two groups: Lewis took one team north to check out the Marias River and see if it went to Canada, while Clark led another group south along the Yellowstone River. On July 26, Lewis’s group ran into eight Blackfoot Indians. He invited them to camp together, but things turned sour the next morning when the natives tried to steal horses and guns. After a quick standoff, Lewis’s men ended up shooting two of the Blackfeet, which was the only violent incident during the whole expedition. They then rode hard for 24 hours to avoid any retaliation. Meanwhile, Clark’s group had a smooth journey. He even carved his name and the date into a sandstone rock formation he named Pompey’s Pillar, in honor of Sacagawea’s son, whom he nicknamed ‘Pomp’.
On August 12, Lewis and Clark met up again at the Yellowstone River’s mouth. They then made their way back down the Missouri River, covering about 70 miles (112 km) each day, and got to the Mandan villages by August 14. They hung out there for a couple of days while the captains took care of some business with the Mandan and Hidatsa leaders. When it was time to leave, the Corps said goodbye to Charbonneau, Sacagawea, and little Jean Baptiste, who decided to stay behind. The team then sped down the Missouri River and finally arrived in St. Louis on September 23, 1806. After two years and four months, the Corps of Discovery wrapped up its journey, marking what many consider the most important overland exploration in US history.
Aftermath & Legacy
The Lewis and Clark Expedition was definitely a big win. Even though it didn’t find the Northwest Passage, it accomplished its main goal of exploring and mapping the area between the Mississippi River and the Pacific Ocean. Plus, having American explorers out there helped strengthen the U.S.’s claim to the Oregon Country. They returned with around 140 detailed maps and tons of records and samples of natural resources and plants that were new to Europeans. Throughout their journey, they identified 178 new plant species and 122 animal species and subspecies. Their expedition also opened the door for more settlement in the Louisiana Territory and boosted fur trading in the Pacific Northwest. Inspired by what Lewis and Clark achieved, other westward expeditions followed, like Zebulon Pike’s trips into what’s now Colorado and New Mexico.
For all their hard work, Lewis and Clark got double pay and 1,600 acres of land each. In 1807, Lewis became the governor of the Louisiana Territory. He managed to publish the first territorial laws and tried to stick to treaties with Native Americans, but he faced criticism over how he handled land claims and his lack of communication with his bosses. Lewis struggled with depression, and during this time, his drinking got worse. On October 11, 1809, while on his way from St. Louis to Washington, D.C., Lewis died from gunshot wounds to his head and chest; people still debate whether it was suicide or murder. Meanwhile, Clark was made a federal Indian agent and later became the governor of the Missouri Territory. After Sacagawea passed away from an illness in 1812, he took on the role of legal guardian for Jean Baptiste. In 1814, Nicholas Biddle published the journals of Lewis and Clark in his book History of the Expedition Under the Commands of Captains Lewis and Clark. However, Biddle left out a lot of the scientific discoveries from the expedition, so Lewis and Clark didn’t get credit for many of the things they found in nature.
