The captains named the encampment Fort Mandan in honor of their neighbors. As befit a military fort, there was a sentry post and the swivel gun was mounted. It would not be needed.

Clark computed their distance from the mouth of the Missouri at 1,600 miles, which would mean an average distance traveled of under eleven miles per day. Upon reaching the Mandans, Meriwether Lewis paid off the French voyageurs who had accompanied them from St. Louis. Some of them immediately headed back downstream, while others remained for the winter. They would return with Corporal Warfington in the spring.

The white men's fort was filled with visitors. There were, of course, the Mandans, led by the chiefs, Big White and Black Cat. Canadian explorers and traders, such as Francois-Antoine Larocque and Charles MacKenzie, spent time with the Corps. Then there was Toussaint Charbonneau, a middle-aged French Canadian, who had won two young Indian girls on a bet and made them his squaws. The girls had been captured by the Hidatsa at the three forks of the Missouri, far to the west.

One of the girls was called Sakakawea (this is the spelling used in North Dakota, and means "Bird Woman" in the Hidatsa language). She was Shoshone and probably around 15 or 16 at he time that she met Lewis & Clark. She was also pregnant with 1er first child.

Charbonneau was eager to be hired on as an interpreter for the rest of the trip and the captains agreed, as much for the native language of his wives as for any skill that he possessed. The interpretation process, however, was laborious. Sacagwea would speak with her husband in Hidatsa, which Charbonneau would translate into French for Drouillard. He then turned that into English for the captains.

While no hostilities broke out during their winter at Fort Mandan, Lewis did have to work hard at times to keep the peace among the tribes. The Mandan, wanting the benefits of trading with the white man all to themselves, had stirred up the Hidatsas with lies about the party's intentions. Lewis tried to smooth things over, but the Hidatsas showed little interest. They had been given no presents and felt that the white men were arrogant.

Also, the Arikara had aligned themselves with the Sioux and attacked a small Mandan hunting party, killing one brave and stealing several horses. Lewis & Clark offered to assist the Mandan in tracking down the offenders, but they were rebuffed. Throughout the entire journey the two captains would never truly understand the complexity of the Native American tribes' relationships with each other or with the white man.

For the most part, however, the winter passed peacefuIly. Lewis and others of the men rode with the Mandans to hunt buffalo. Despite the need for large amounts of meat to feed the party over the long winter, the white hunters took only the tongues of the buffalo. The captains kept the men busy, repairing equipment, making new moccasins for the upcoming trip and hunting.

On New Year's Day, 1805, a group of the men went to the nearest Mandan village, where Cruzatte played his fiddle and York danced, much to the amusement of the natives. A few days later, the Mandans introduced the newcomers to the buffalo dance. During the dance, young braves would offer wives to elders of the viIlage or to the men of the expedition in hopes that the " transfer of power" would lead to successful buffalo hunts.

During the winter Lewis also put his doctoring skiIls, such as they were, to use. He treated an abscess on an Indian child’s back and cut off the frostbitten toes another young boy. If his own men became ill, they were treated in the methods common at that time - bleeding and purging with Dr. Rush's "thunderclapper piIls", that Rush claimed would cure anything. The "cure" was often worse than the illness.

The most important event of the winter was the birth of Sacagawea's son February 11. On the advice of Rene Jessaume, a trader who had long lived the Mandans, a brew containing the rattle of the rattlesnake was administerd to Sacagawea and she gave birth soon after. The baby was named Jean Baptiste, but would be nicknamed "Pompey" or "Pompi" by William Clark.

Although the snow was still deep the ice stilI thick, the men managed break the keelboat and pirogues loose in late February and put them into dry-dock for repairs. As spring neared, the pace the work picked up. Canoes were built to provide additional boats for those headed west. Jerky was made from the meat. The keelboat was caulked and made ready for the return trip to St. Louis. And Lewis continued his work of the winter, writing volumes to Jefferson about what they had seen, how things had gone with the native tribes, and cataloging the various specimens he had collected.

The specimens, Lewis' writings, Clark's map and other material were carefully loaded into the keelboat. On the afternoon of April 7, 1805, Warfington and his men headed the large boat back down the river. It would be the corporal's responsibility to get the boat's contents safely to Jefferson.

At the same time, the permanent party headed west in the two pirogues and six new canoes. The Hidatsas had been to the three forks of the Missouri and told Lewis that it would only take half a day to cross the continental divide. He felt safe in assuring Jefferson that the expedition would achieve its main goal of finding an all-water route to the Pacific. Lewis wrote the president that he hoped to reach the ocean that summer and return to the Mandan villages for the winter, allowing him to arrive at Monticello by September 1806.

Even though the Corps of Discovery was headed into virtually unknown territory, Meriwether Lewis concluded his letter to Jefferson on an extremely optimistic note: "I can foresee no material or probable obstruction to our progress, and entertain therefore the most sanguine hopes of complete success. At this moment, every individual of the party are in good health, and excellent spirits; zealously attached to the enterprise, and anxious to proceed; not a whisper of discontent or murmur to be heard among them; but all act in unison, and with the most perfict harmony. With such men I have everything to hope, and but little to fear." It is perhaps a good thing that Lewis could not at that moment comprehend the challenges that awaited them.