Missouri and Oto:
The Missouri and Oto Indians lived along the Missouri River near the border of Missouri and Nebraska. They were buffalo hunters and farmers who lived in earth-covered lodges. Smallpox had decimated both tribes by the time Lewis and Clark arrived, prompting the survivors to move together into villages. On Aug. 2, a small group of Missouris and Otos arrived at the expedition?s camp at Council Bluff (currently the site of Fort Atkinson, and miles from what is now Council Bluffs, Iowa). The next day, Lewis and Clark conducted the first formal meeting as ambassadors from the United States to the western Indians. During the council, the Indians were told they were the "children" of a new "great father" who would provide them with trade goods in place of the French and Spanish. The Missouris and Otos were advised to make peace with other Indian tribes in order to bring the trade Lewis promised. It was a speech Lewis and Clark would deliver many times as they encountered new tribes.

Yankton Sioux:
The Yankton Sioux were the first of the classic semi-nomadic Plains tribes encountered by the expedition, mounted hunters who lived in conical teepees near what is now Yankton, S.D., The first meeting between the Yankton Sioux and the expedition took place on Aug. 30, 1804, at Calumet Bluff, near the site of Gavins Point Dam in South Dakota. Some 70 Yanktons journeyed to the expedition?s camp, proceeded by musicians. During the meeting, the Yankton chief told Lewis and Clark his people who were poor needed a reliable trading partner - and would appreciate gifts of rifles, ammunition and possibly whiskey from the expedition?s stores. Instead, they received and accepted an invitation to send a delegation to Washington D.C., to begin trade discussions with President Jefferson. During the meeting, Yankton warriors demonstrated their proficiency with bow and arrow, and performed ceremonial dances.

Teton Sioux:
The Teton Sioux occupied two villages near present-day Pierre, S.D. Among French and Canadian traders, as well as neighboring tribes, the Tetons had a reputation as an aggressive and powerful nation intent on controlling traffic on the Missouri River through their territory. They did this through intimidation and use of force, frequently forcing traders to turn over their goods. At the first council with the leaders of the Teton tribe, the Lewis and Clark expedition went through its practiced ritual for meeting Indians, parading in uniform and demonstrating an air gun. The display did little to impress the Tetons, who perceived the Americans as competitors for control of trade in the region. Tensions increased between the two sides, leading to several confrontations between the Tetons and the expedition that nearly resulted in armed conflict.

Arikara:
Originally numbering some 30,000, the Arikara were farmers who occasionally hunted buffalo and lived in earth-lodge villages surrounded by defensive palisades and tilled fields of beans, squash and corn. Beginning in the 1780s, they were struck by a series of smallpox epidemics that left only a small percentage of the original population. As the Lewis and Clark expedition entered the Arikara homeland in what is now northern South Dakota, it found one deserted village after another. The explorers eventually found three inhabited Arikara villages, all on a three-mile-long island at the mouth of the Grand River, inhabited by about 2,000 people. The Arikara grew food for themselves, but also to trade with the Teton Sioux in exchange for guns and other goods obtained from the French and British. Negotiations between the expedition and the Arikaras centered on the prospect of trade with the United States, in which the Indians were interested. Like the Oto and Missouri, the Arikara agreed to send a representative to visit President Jefferson. Lewis also encouraged the Arikaras to make peace with their chief enemy, the neighboring Mandans.

Mandan:
With their Hidatsa neighbors, the Mandans occupied the center of a vast trading network along the Upper Missouri River and across the northern plains. The Corps of Discovery reached the two Mandan villages in the fall of 1804 and stayed the winter in a fort they built near today?s Washburn, N.D. Like the Arikara, the Mandans and Hidatsas were primarily farmers inhabiting villages of earth-covered lodges, hunting buffalo, deer and elk to supplement their crops of corn, beans and squash. Each autumn, following the harvest, European traders and representatives of such tribes as the Cree, Cheyenne, Assiniboin, Crows and Teton Sioux descended upon the Mandan villages to exchange a wide range of goods for Mandan corn. The tribe welcomed the expedition to spend the winter in the area, and supplied the Americans with food throughout the winter in exchange for a steady stream of trade goods.

Hidatsa:
The Hidatsas, allies of the Mandans, lived in three villages along the Knife River in central North Dakota. Hidatsa villages were similar to their Mandan counterparts, comprising irregular clusters of earth lodges around a central plaza. Like the Mandans, the Hidatsas were heavily involved in the northern plains trade network, growing corn, tobacco, squash and beans to exchange for everything from meat to horses. Unlike the Mandans, the Hidatsas regularly sent war parties against the Shoshones and Blackfeet. It was during one such raid that the young Shoshone girl Sacagawea was captured and brought to the Hidatsa villages, where she and her husband, trader Toussaint Charbonneau, joined the Corps of Discovery. The combined population of the two Mandan and three Hidatsa villages in 1804 was about 4,500 people - larger than either St. Louis or Washington, D.C.

Assiniboin:
The Assiniboins in 1804 occupied northeastern Montana and the adjoining area of Canada, regions claimed by the British, with whom the Assiniboins traded dried meat for guns, brass kettles and cloth. As the British could not meet all of the Assiniboins? trading needs, the tribe ventured south each fall to the great marketplace of the Mandan and Hidatsa villages. There, they learned of the presence of the Corps of Discovery and arranged a meeting between several prominent Assiniboins and Lewis and Clark. Although the meeting was without incident, the Assiniboin representatives warned that developing trade between the Mandans and Americans could bring military retaliation. As a result, Lewis and Clark were nervous about encountering Assiniboin bands as they traveled west along the Missouri the following spring. Although the expedition found signs of the Assiniboins - tracks and abandoned camps - the encounter they feared never came.

Blackfeet:
The Blackfeet of northern Montana traded regularly with British merchants based in Canada, allowing them to obtain an ample supply of guns and ammunition. Thus armed, the Blackfeet were able to dominate the Nez Perce and Shoshone, their mortal enemies. While traveling in the vicinity of today?s Glacier National Park in July 1806 during an exploration of the Marias River watershed, Meriwether Lewis and several companions encountered Eight Blackfeet warriors. Both groups were nervous. Lewis told the Blackfeet that the United States wanted to seek peace among all the Indian tribes of the west, pointing out that the Shoshone and Nez Perce had agreed to this peace and would be receiving guns and supplies. To the Blackfeet, this represented a threat. That night, the Blackfeet attempted to steal the expedition?s guns. In the chaos that ensued, two Blackfeet warriors were killed, and the Americans fled. The incident marked the first bloodshed between western Indians and representatives of the United States government, and was the only instance when the members of the Corps of Discovery fired their weapons in anger.

Shoshone:
The Shoshone were also known as the Snake, and lived on both sides of the Continental Divide in Idaho and Montana. Those on the west lived in grass huts and relied primarily on salmon for food; those on the east lived in tepees and hunted buffalo. In the years before Lewis and Clark arrived, however, the eastern bands had been driven from the plains into the mountains by their enemies - the Blackfeet, Atsina and Hidatsa - who had acquired muskets from Canadian fur traders. The Shoshone still ventured onto the plains to hunt, but this put them at considerable risk. (The Shoshone traded with the Spanish, who had refused to give them firearms.) The Shoshone had horses, though, and the Corps of Discovery had counted on being able to obtain them through trade in order to cross the Rocky mountains. Sacagawea was a member of the Lemhi Shoshone band by birth, and proved useful in negotiating between the explorers and her people, whom the Corps of Discovery encountered in August 1805 in the Lemhi Valley near Tendoy, Idaho.

Nez Perce:
After a difficult crossing of the Bitterroot Mountains in Idaho, during which the members of the Corps of Discovery nearly perished from cold and hunger, they encountered the Nez Perce, who lived in villages along the Clearwater and Snake rivers. The Nez Perce welcomed the explorers, fed them buffalo, salmon and bread made from the dried root of the camas plant, and allowed them to stay long enough to recover from the grueling hike across the mountains. Members of the tribe helped Lewis and Clark find timber for canoes, and the captains left their horses temporarily in the care of the Indians. The expedition returned to the Nez Perce villages during the return journey in May 1806 to reclaim their horses, and remained among the tribe for nearly two months while waiting for the snow to melt sufficiently in the Bitterroots to make the arduous crossing possible.

Walla Walla:
The Corps of Discovery first encountered the Walla Wallas in October 1805 while rushing to reach the Pacific, and declined the tribe?s invitation to stop. The expedition did visit the village on the way home in April 1806. The tribe lived near the confluence of the Snake and Columbia rivers in Washington, and welcomed the Americans with gifts of a white horse, firewood and roasted fish. In exchange, Clark gave the Walla Walla chief his sword, 100 rounds of ammunition and some trade items. When the Americans decided to leave after only a day, the Walla Wallas persuaded them to stay another night in return for more horses, food, canoes and information about the trail ahead. That evening, a large party of Yakimas joined the Walla Wallas, and the entire group - including the Americans - enjoyed a rousing celebration featuring music and dancing.

Wishram:
Occupying the north side of the Columbia River at the Dalles, the Wishram controlled an enormously productive salmon fishery that provided them with enough fish to supply their own needs as well as to produce a surplus for trade. (Clark estimated in his journal that the Wishrams had 10,000 pounds of dried salmon stored at one village, where the inhabitants dwelled in plank houses.) Accordingly, tribes from throughout the Columbia basin, including the Yakima, Walla Walla and Nez Perce, brought meat, roots, berries, animal skins and horses to trade for the Wishrams? dried salmon, which would keep for a long time and was a reliable food source during the winter. Lewis and Clark stayed with the Wishram for a short time; before they left, they negotiated a peace agreement between the Wishram and the Nez Perce, and celebrated the settlement that evening with music and dancing.

Tillamook:
The Tillamooks lived along the northern Oregon coast between the mouth of the Necanicum River and Tillamook Bay. The Tillamook village of Necost was the southernmost point reached by the Corps of Discovery on the Pacific coast; members of the expedition journeyed from their winter residence at Fort Clatsop to the beach near Necost, 35 miles away, when they learned that a large whale had washed ashore there. Hoping to obtain some of the meat, Clark and his men found instead that the Tillamooks had quickly stripped the whale to the bone. They exchanged trade goods for 300 pounds of blubber and some oil.

Clatsop:
The Clatsops, numbering about 400, occupied three villages on the south side of the Columbia River at the northwestern tip of Oregon. The tribe told Lewis and Clark that there were plenty of elk on the their side of the river, which led the Corps of Discovery to build its winter quarters - named Fort Clatsop after the tribe - nearby. Although relations between the expedition members and their Indian neighbors were mostly cordial, Lewis authorized the theft of a Clatsop canoe shortly after the group left on its return journey. It was an atypical incident, perhaps reflecting the stress of the long, wet winter and the expedition?s eagerness to get home. Lewis and Clark had already given Fort Clatsop and all its furniture to one of the local tribal leaders in gratitude for his friendship and hospitality.

Chinook:
Members of the Lewis and Clark expedition developed a low opinion of the Chinooks, relatives of the Clatsop tribe who lived on the north side of the Columbia River in Oregon. Although admiring the Chinooks? skill as canoe builders and navigators, Lewis and Clark found them to be difficult trading partners - a result, perhaps, of the tribe?s long acquaintance with white traders arriving by seas - and were dismayed by their habit of stealing any item left unsecured. Visits by the Chinooks to Fort Clatsop were limited, and the Indians were not allowed to stay overnight.