Wikipedia
The Sinixt (also known as the Sin-Aikst or Sin Aikst, "Senjextee", "Arrow Lakes Band", or — less commonly in recent decades — simply as "The Lakes") are a First Nations People. The Sinixt are descended from indigenous peoples who have lived primarily in what are today known as the West Kootenay region of British Columbia in Canada and the adjacent regions of Eastern Washington in the United States for at least 10,000 years. The Sinixt are of Salishan linguistic extraction, and speak their own dialect ( sn-selxcin) of the Colville-Okanagan language.
Today they live primarily on the Colville Indian Reservation in Washington, where they form part of the Confederated Tribes of the Colville Reservation, which is recognized by the United States government as an American Indian Tribe. Many Sinixt continue to live in their traditional territory on the Northern Side of the 49th Parallel, particularly in the Slocan Valley and scattered amongst neighbouring tribes throughout BC, however the Canadian Government declared the Sinixt extinct in 1956.