Selkirk Mountains, subdivision of the Columbia Mountains and considered part of the Rocky Mountain system. Mostly in British Columbia, Canada, and touching Idaho and Montana in the United States, the Selkirk Mountains extend for 200 mi (322 km) between the Columbia River, on the west and north, and the Purcell Mountains, on the east. The Selkirk's higher northern peaks include Mt. Sir Sanford (11,590 ft/3,533 m), the range's highest. Glacier and Mt. Revelstoke national parks are also in the northern end. Illecillewaet is the Selkirk's largest glacier.