Bastion Peak is a 2,994-metre summit in the Canadian Rockies on the Alberta-British Columbia boundary, rising in the Tonquin Valley between Jasper National Park and Mount Robson Provincial Park. Édouard-Gaston Deville named it in 1916 because its shape suggested a castle bastion, a fitting image beside nearby Turret Mountain. Mount Geikie is its greater parent. The mountain stands in a subarctic climate marked by cold, snowy winters, mild summers, and temperatures that can drop below −20 °C with even colder wind chills. Its runoff divides eastward to Athabasca River tributaries and westward to Fraser River tributaries.