Prior to the arrival of European explorers, the Klamath people lived in the area around the Upper Klamath Lake and the Klamath, Williamson, and Sprague rivers. They subsisted primarily on fish and gathered roots and seeds.
The Klamaths, Modocs, and the Yahuskin, a band of Klamath erroneously believed to be a group Paiute or Shoshone, signed a treaty with the United States in 1864, establishing the Klamath Reservation to the northeast of Upper Klamath Lake. The treaty required the tribes to cede the land in the Klamath Basin, bounded on the north by the 44th parallel, to the United States. In return, the United States was to make a lump sum payment of $35,000, and annual payments totalling $80,000 over 15 years, as well as providing infrastructure and staff for the reservation. The treaty provided that, if the Indians drank or stored intoxicating liquor on the reservation, the payments could be withheld; the United States could also locate additional tribes on the reservation in the future. The tribes requested Lindsay Applegate as the agent to represent the United States to them. The Indian agent estimated the total population of the three tribes at about 2,000 when the treaty was signed.
Since termination of recognition of their tribal sovereignty in 1954 (with federal payments not disbursed until 1961), the Klamath and neighboring tribes have reorganized their government and revived tribal identity. The Klamath, along with the Modoc and Yahooskin, have formed the federally recognized Klamath Tribes confederation. Their tribal government is based in Chiloquin, Oregon.
Both the Klamath and the Modoc called themselves maqlaqs, meaning "people". When they wanted to distinguish between themselves, the Klamath were called ?ewksiknii, "people of the [Klamath] Lake", and the Modoc were called moowatdal'knii, "people of the south".