[2][3] The Okanagan are closely related to the Spokan, Sinixt, Nez Perce, Pend Oreille, Secwepemc and Nlaka'pamux peoples of the same Northwest Plateau region.

[1] At the height of Okanagan Syilx culture, about 3000 years ago, it is estimated that 12,000 people lived in this valley and surrounding areas.

The Syilx employed an adaptive strategy, moving within traditional areas throughout the year to fish, hunt, or collect food, while in the winter months, they lived in semi-permanent villages of kekulis, a type of pithouse.

[5] When the Oregon Treaty partitioned the Pacific Northwest in 1846, the portion of the tribe remaining in what became Washington Territory reorganized under Chief Tonasket as a separate group from the majority of the Syilx, whose communities remain in Canada.

[11] Nsyilxcn is an Interior Salish language that is spoken across the Canada–United States border in the regions of southern British Columbia and northern Washington.