Mount Slesse is a striking peak in British Columbia’s Cascade Mountains near Chilliwack, noted for its sharp profile, steep walls, and major climbing routes, especially the Northeast Buttress, one of North America’s classic rock climbs. Formed largely from granitic rocks tied to the Chilliwack batholith, the mountain also preserves older metamorphic rock on its summit ridge and west face. First climbed in 1927, it later became internationally known both for demanding ascents and for the 1956 crash of Trans-Canada Air Lines Flight 810, which killed all 62 aboard, making the mountain a place of both recreation and remembrance.