Most of the plateau of tribes lies in one country. Which one?

Four of these tribes are the Yakama, Umatilla, Warm Springs, and Nez Perce. These tribes are known as "Plateau tribes" because their home is called the Columbia Plateau. The Plateau Indians are still here today. Many live in special areas called reservations that were set aside for them in the 1800s

And they are the tribes of the northern

tribes of nothern