The obverse (front) of the Jefferson medals had a formal bust of President Jefferson in low relief, along with his name and the date he entered office. The reverse showed clasped hands and bore the motto "Peace and Friendship." This design depicted Indian nations as coequals of the United States. The same pattern for the reverse continued in use until 1849. Only the presidential portraits, especially commissioned for each medal, changed during these years. The Jefferson medals were not made of solid silver, but were hollow because of the way in which they were fashioned. The obverse and reverse were struck separately on thin planchets of silver, and then joined by a silver band. Three sizes of medals were made, with diameters of 4", 3", and 2 1/4". The " Season Medals," were made in Great Britain during George Washington's second term, were designed by the renowned American artist John Trumbull. They depicted cattle raising, the sowing of wheat, and a woman spinning. These themes expressed in visual terms the recurring desire of the government to "civilize" and "educate" American Indians. The Season Medals were not popular, because Native American chiefs did not recognize the validity of a medal without the likeness of the President of the United States.

Although the men of the expedition did not know what to expect on their trek, they were prepared to meet the various Indian tribal groups and curious about what they would be like. Patrick Gass, in his journal first published in 1807, mentioned at the outset of the journey that "we were to pass through a country possessed by numerous, powerful and warlike nations of savages, of gigantic stature, fierce, treacherous and cruel; and particularly hostile to white men." It is fairly certain that by the time Gass returned, his assessment of American Indians was quite different than when he set out on the journey.

Whether Lewis and Clark knew it or not, they were the "spearpoints" of an invasion of American Indian homelands in the West. Whether or not their actions were deliberate, they touched off an invasion rarely paralleled in world history, displacing entire peoples and tribal groups with Anglo settlers, backed by the U.S. Army and English land law. It is for this reason that many native peoples see no reason to be happy about the Lewis and Clark Bicentennial, and why this event should be looked upon by all as a "commemoration" rather than a "celebration." For this reason it is also difficult to discuss such a complex topic in a small amount of space. Therefore, perhaps it is best to let the explorers speak for themselves.

Although Lewis and Clark and their men did not comment on every group of Indians they met with, they left behind various accounts of different tribal groups and their interactions with them. The following series of descriptions is organized according to tribe. Although the information is often inaccurate, and not every tribe is handled equally or in some cases discussed at all, it is hoped that these descriptions will give the reader some idea of what the expedition members experienced in 1803-1806.

Tribal groups on which Lewis and Clark collected information, in chronological order: