This is a photo of Chief Ka-Lit-In of the Cayuse Indians of the North American Plateau. It was taken by Lee Major Moorhouse, circa 1900.
The Cayuse people lived on the Columbia Plateau in what is now southeast Washington and northeast Oregon. They call themselves the Tetawken, which means, 'we, the people.' They were famous horse breeders, and the small breed of horse, the cayuse "indian pony," is named after this group of Native people. They were also noted by early explorers for the bravery, and for using their riding prowess to intimidate other tribes.
By 1855 the Cayuse had settled on the Umatilla Reservation near Pendleton, Oregon. By 1990, they were among the smallest of tribes in the United States, numbering only 126 members at that time.
You can read more information about the history and culture of the Cayuse Indians on the website of the Confederated Tribes of the Umatilla Indian Reservation.