The expedition started to move upstream on the Mississippi River. The power of the river far outstripped the Ohio, which underlined the need for more men to help handle the boats. “The tiny fleet slowly inched its way north” (121) against the current, until it eventually reached St. Louis, a city that still considered itself a colony of Spain in Upper Louisiana. Only forty years old at this point, St. Louis was small, but the center of the lucrative fur trade, which produced luxurious pelts sold for fortunes in Europe. St. Louis welcomed Lewis and his crew, happy to provide supplies they could charge to the army. The expedition chose to wait out the winter near St. Louis at the mouth of Wood River, where they could also select and train men to join the expedition. Lewis also gathered data on the pioneers and settlers of St. Louis. He found that pioneers came from the east coast of America, as they thought, but also from Europe, driven by hope for good farming land. Jefferson had hoped that he could get pioneer farmers to move from Upper Louisiana to Illinois, freeing Upper Louisiana land for the use of Indigenous peoples and easing hostility between the settlers and the tribes. However, Lewis saw that the settlers would not easily give up the land they had colonized, and no force could keep them from expanding regardless of permission given or denied.

The crew swelled from twelve to twenty-two men plus three sergeants, Lewis and Clark, York, an interpreter named Drouillard, and Seaman the dog. This was twice the number that was authorized, but Lewis and Clark still worried that the party was too small to survive. They wanted to remain small so as not to seem a threat to Indigenous peoples they encountered, but also they needed to have the numbers to hold their own in a fight if it came to that.

While in St. Louis, the official transfer of power from Spain to France, and then from France to America, took place in a ceremony where Lewis was invited to act as chief official witness. The complex transfer of power reflected the confused nature of state authority in such a remote place.

Lewis and Clark, noting the warmth of approaching spring and the new swell of water in the river, started to prepare to leave the St. Louis area. They split up to gather new supplies to replenish their stocks before they departed, making sure to buy Indigenous trade goods, whiskey and provisions to ensure that they did not run out.

Lewis received unwelcome news from the current Secretary of War: Clark had not received a captain’s commission, but instead only a lieutenancy. Frustrated, Lewis decided not to tell the crew of the expedition of Clark’s demotion, instead keeping it a secret between himself and Clark. Lewis was mostly concerned with making sure that the men saw Clark as an equal authority.

At 3: 30 pm on May 21st, they departed the St. Louis area to the sound of cheers from observers on the riverbanks. The departure from St. Louis represented a tipping point for the expedition: for the next two years, they were cutting themselves off from civilization. They would no longer be able to receive letters, commissions, fresh supplies, or reinforcements. This would be a truly independent mission, “such as the U.S. Army had not previously seen and never would again” (139). Lewis and Clark were free to use their own judgment to lead their men and ensure the success of the expedition, but they also bore the heavy burden of responsibility for any and all failures or dangers.

Navigating the “springtime high, almost flood stage”(140) Missouri River while traveling upstream was a profound challenge. When the wind was in their favor, they could raise a sail on the keelboat or the two lighter pirogues, but if it wasn’t, they had to use poles to shove the boat along the riverbed and oars to propel it forward. The physical labor involved in fighting against the river was incredible. The river was full of obstacles they had to avoid as well, like logs, rocks, and sandbars.

Since “Clark was the better waterman, Lewis the better scientist” (141), Clark often managed the demanding task of piloting the keelboat while Lewis traveled onshore along the river. None of Lewis’s journal entries exist for this section of the expedition, though he was likely surveying the land for farming and settling potential, as well as discovering and recording new species of plants and animals.

As the expedition traveled towards the Kansas territory, the threat of conflict with Indigenous people became more and more real. “The last thing Lewis wanted was an Indian fight” (145), and he was determined to avoid the prospect. He also knew that establishing friendly trade relations with Indigenous peoples was the best outcome. Lewis believed that the best way to encourage friendly relations would be to stay stealthy while seeming like a bad target for an ambush. Constant vigilance in the form of sentinels and daily inspections of rifles and blunderbusses were implemented to that end. Lewis hoped that there would be no conflict, and that he could persuade Sioux chiefs to travel to Washington to meet Jefferson.

Two men snuck some more whiskey than they were allowed while on guard duty, and were sentenced to receive lashes on the back for the transgression. Another man fell asleep on guard duty and was sentenced to four hundred lashes, one hundred a day for four days. These draconian punishments reflected the importance placed on obedience and unit cohesion, since their only protection was their own vigilance.

By July 30th, the expedition was 640 miles up the Missouri River, and they had still not seen a single Indigenous person. Unbeknownst to them, the Sioux spent the summer months hunting buffalo on the prairie, not trapping or fishing on the river.

Both Lewis and Clark were astounded by the sheer size of the lands they explored and the new species that abounded. They spent hours examining and describing their finds, including terns, a bull snake, and a “prairie wolf” or coyote. One of the privates managed to kill a buffalo, which the crew feasted on that night.

The proximity of the buffalo foreshadowed the proximity of Indigenous people, particularly the Sioux. Jefferson had told Lewis that the most important goal of the expedition was to successfully reach the West Coast of the continent and travel back with vital data. If the Sioux, feared for their prowess in battle, tried to stop them, they would have to shoot their way through and keep moving. However, they hoped to have Sioux assistance, not hostility. To that end, Lewis and Jefferson had meticulously chosen gifts to give to the tribes. These gifts included beads, mirrors, awls, tomahawks, tobacco, red face paint, and whiskey. Lewis knew that the firepower of American rifles would pose the most compelling draw for the Sioux, but he could not bring along rifles as gifts because of the weight. He would have display the superiority of American craftsmanship over the cheap British shotguns to which the Sioux had access, then promise later delivery.

On August 3rd, 1804, Lewis and Clark were able to make contact with members of the Oto tribe in what is now Council Bluffs, Iowa. An Oto hunting party discovered them, and through their interpreter, Lewis invited delegates to come back for gifts and a speech.

In his speech, Lewis referred to Jefferson as their new great father, who loved “his red children” (157) and desired them to become prosperous alongside white traders and to make peace with the other Native Americans in their vicinity. Crucially, Lewis’s only threat to them to discourage hostility was that if they were harmed, no white traders would ever return to these lands. Without European trade goods, the Otos and other neighboring tribes would be seriously vulnerable to other tribes who still had access to guns and powder. The speech fell flat afterwards, because the gifts so carefully prepared by Lewis turned out to be unimpressive to the Oto. The Oto chiefs responded by promising to follow the rules, saying they were happy to have a new “father,” and finally requesting gunpowder and whiskey. Lewis obliged, wanting to please. However, days later one of the chiefs returned to them naked, “to emphasize his poverty” (159). From their perspective, the expedition possessed all kinds of wonderful treasures and refused to hand them out to the tribes, despite saying that their new father loved them. If the white men wanted universal peace, they needed to provide a more profitable solution than a few symbolic gifts. Lewis and Clark refused to hand over the gunpowder and whiskey the Oto requested, instead giving some tobacco, paint, and beads. Dissatisfied, the chief went on his way. This encounter left a bitter taste in the mouths of Lewis and Clark: the Oto were a small, poor tribe, but the Sioux were not. If the Oto felt disrespected by the meager gifts, the Sioux were likely to feel the same.

After this encounter, Sergeant Charles Floyd, desperately ill from what was likely a ruptured appendix, died on August 20th. The first US soldier to die west of the Mississippi, Floyd was buried with all the honors of war, and the river near his gravesite named the Floyd River. Then, one of the privates, Shannon, disappeared on a hunting trip, likely falling prey to an accident. “The expedition was almost 10 percent reduced in fighting strength” (161) before they even met with the Sioux.

Private Shannon’s footprints were seen along the river as they progressed, leading Clark to believe that Shannon was ahead of the group but believed himself behind, and was trying to catch up. On September 11th, they found a starving Shannon sitting by the river, having lived on wild fruits for the last two weeks.

On September 23rd, some Sioux spotted the camp and swam to meet them. Lewis and Clark arranged to meet the chiefs upriver at their villages. On the 24th, they met with the chiefs, who gave large amounts of freshly hunted buffalo as a gift. They found with consternation that their interpreter could not actually speak the Sioux language as well as he thought, and so Lewis and his men started to display their “traveling medicine show” (169) of European wonders, including Lewis’s airgun. They then presented the chiefs with symbolic military coats and the Jefferson medals. The chiefs were displeased by this ungracious display and said so, refusing to let the expedition leave without more gifts. Fed up, Clark ordered the men to load their weapons and ready for a fight. Another chief, Black Buffalo, defused the situation by forcing the other chiefs to stand down. Clark upbraided the chiefs for their perceived rudeness, and luckily the chiefs tried to placate him. As the crew readied to depart, the Sioux warriors grabbed the lead ropes to prevent the boats from leaving, demanding symbolic gifts of tobacco to show their dominion over the river, Lewis and Clark swallowed their pride after a long argument, including the brandishing of weapons, and threw them tobacco. Jefferson’s instructions to show goodwill to the Sioux had been ignored at this juncture, leading to a grave risk to the expedition. Lewis and Clark had acted in a “headstrong and rash” (175) manner, leading to bad feelings and resentment among one of the most powerful tribes in America. They had expected the Sioux to respect their traditions while refusing to do the same for them, and were surprised and angered when that strategy did not work. However, they also suffered from a profound lack of information on the Indigenous peoples and the land they inhabited, the very problem they were meant to address in this expedition.

North of present-day Bismarck, North Dakota, the Mandans and their neighbors the Hidatsas were the center of the Northern Plains trade, their villages crowded with Indigenous people from all over the continent as well as European traders. On the 24th of October, Lewis, Clark, and the Arikara chief finally met with Chief Big White and his second-in-command, Little Raven. The expedition’s crew was shocked by the sheer size of the villages, with over four thousand people, almost one-third of them trained warriors. Learning from their past failures, Lewis made it clear that if they were attacked, all trade from the US would be stopped and the military would come and destroy their settlements. Luckily, the Mandans understood the benefits of giving a warm welcome to this advance party. They were so helpful that Lewis and Clark decided to settle near them for the winter. The Mandans “were delighted that the expedition would spend the next five months as their neighbors” (184). Experienced in the subtleties of trade, the Mandans took the opportunity to set up strong friendly relations to facilitate economic growth in the future. Relieved, Lewis and Clark set about building their overwinter home, Fort Mandan. On November 4th, a trader named Toussaint Charbonneau arrived at camp. He brought with him his two wives from the Shoshone tribe in the Rocky Mountains. His wives could speak Hidatsa and Shoshone, and because of this, the captains eagerly accepted his offer to join them. Charbonneau and one of his wives, the 15-year-old pregnant Sacagawea, joined the expedition, while the other stayed behind.

It became clear during the fall months that the different tribes were using the presence of the expedition for their own political gain. The prospect of a treaty of perpetual peace also posed political problems, since chiefs proved themselves via warfare, not prosperity. Small skirmishes broke out between groups of Sioux, Arikara, and Mandan, reflecting this tension. Lewis and Clark continued “meddling in affairs they did not understand” (189), and only the patience and protection of the Mandan ensured their survival. They provided the expedition with huge amounts of Indian corn, beans, and squash. Additionally, they informed the white men of nearby game when they appeared and loaned them horses to join in the hunt.

The brutal cold of the northern plains posed a great danger to the expedition during the winter. Lewis and Clark both recorded that the Mandan people seemed to have a much higher tolerance for cold than themselves, often spending the night outside in freezing weather while hunting without ill effects. The Mandans and the Americans continued their friendly relations, celebrating together American holidays as well as Mandan ceremonies.

The Mandan also used Lewis’s medical training to address some of their problems. Issues like abscesses and frostbite were successfully addressed with Western medical treatments, leading to gratitude and trust from the Mandans. Among the American crew, the most pressing issue was syphilis, a disease that nearly every crewmember had, though Lewis and Clark never recorded treating themselves for it. Sacagawea also gave birth under Lewis’s supervision, delivering the infant Jean-Baptiste. The unexpected presence of an infant was welcome in the camp of homesick men.

The blacksmithing skills of one of the privates, John Shield, allowed them to continue to trade in axes and toolmending in exchange for corn. The food supplies of the Mandan were crucial to the survival of the expedition through its first winter, since the Americans were not at all prepared for the scarcity and brutal conditions of the prairie winter.