The history of the North American First Nations is not something we have terribly much reliable information on, so there is a tendency on the part of people doing this assignment to assume that their Native American ancestors had been living in whatever place they were fist encountered forever. That much, at least, is not correct in many cases, so here is a list of caveats of which one ought to be mindful:
Seventeenth - nineteenth centuries - the good life on the high plains: The life style of the Plains Indians - the classic Indian culture of the westerns - didn't exist prior to the introduction of horses to North America by European settlers. Access to horses enabled people inhabiting the lands adjacent to the plains to move onto them and make a full-time living off of bison hunting. Where did the classic plains nations live prior to the introduction of horses?
Fifteenth - nineteenth centuries - Florida pioneers: The aboriginal nations of Alabama and Georgia formed the Creek Confederacy. Their folklore indicates that they had migrated to that location from a land of high mountains, so if any of your ancestors were Creeks in 1490 CE, you can assume that some of their ancestors lived in the Rocky Mts in 1000 CE.
Moreover, the Creeks had a pioneering offshoot - the Seminoles of southern Florida. In fact, the word "seminole" is Creek for "pioneer." Thus, if you had Seminole ancestors in 1800 CE, you should assume that some of their ancestors were in Georgia or Alabama in 1490 CE.
Eighteenth - nineteenth century Canada - a composite people: Canada was initially colonized by the French, who, unlike English settlers farther south, were more interested in trade with Native Americans for forest products than in driving them out to establish agricultural communities. From the beginning, French settlers intermarried extensively with Indians. (The husband of Lewis and Clark's guide Sacajawea was French.) The result was not merely considerable gene flow between Canadian natives and settlers, but the creation of a new nationality - the Metis. These people are spread throughout the Canadian prairie provinces and trace their ancestry in roughly equal parts to Native Americans; French; and Scottish, Irish, and Bretons. If your ancestors are from the prairie provinces or upper plains states, take seriously any family folklore about ancestry from these groups.
Nineteenth century USA - forced deportations: This century saw the forced settlement of Native Americans on reservations or in "Indian Terretory" - the future state of Oklahoma. The Indian nations that escaped this tragedy were few and far between (most natably the Navajos, who still occupy most of their ancestral lands). Among the biggest losers were the "Five Civilized Nations" of the southeast, the:
Additionally many of the nations of the southern Great Plains were confined to reservations in western "Indian Territory." these included the:
Prehistory: If only we knew more. Everything is speculative, based mostly on the distribution of language groups. Two patterns are worth noting: