LH> As a matter of fact, the Lakota had only been in the northern Great Plains and Black Hills areas for about one hundred years,having been driven from Minnesota by the Cree around 1760.They took the buffalo-rich plains from the Arikara and Kiowa. In 1776 the Oglala, Standing Bull found the Black Hills and they moved into that area as well. Allied with the northern Cheyenne they fought the Crow for THEIR traditional hunting grounds and the Cheyenne eventually took them.
It is a mistake to assume that the American Tribes spheres of influence were static. They moved as need or desire directed them and some of them were quite expansionistic.
There is an article in the October issue of Smithsonian on the Bozeman Trail that goes into this.

troll