A dramatic peak midway between Banff and Lake Louise, named by Sir James Hector in 1858. Castle Mountain exemplifies “castellated” or layer-cake topography; tiered cliffs separated by horizontal ledges; and was the site of Richard George McConnell’s 1886 discovery of the McConnell Thrust, proving that older Cambrian rocks had been shoved over younger Cretaceous strata.

Geology. The mountain is primarily Middle Cambrian carbonates and shale. The Eldon and Pika formations (limestone and dolomite) form the vertical fortress walls; Gog Group quartzites underlie the base; Stephen Formation shale erodes faster than carbonate, creating the shelves between cliffs. The Castle Mountain Fault; a major thrust; runs along the base, with Cambrian rock thrust over Cretaceous; glacial plucking and abrasion carved the towers along vertical joint planes. Silver City lies at its foot.

Indigenous significance. To the Siksika (Blackfoot) the mountain is Miistukskoowa; a sacred site tied to Napi (Old Man) in creation stories, a landmark for travellers, and a source of hunting grounds, lodgepoles, and medicinal plants. Land at the foot was taken from the Siksika in 1908 without consent; a $123 million land claim settlement was reached in 2016. Interpretive signage in the Blackfoot language was unveiled in 2022.

Naming controversy. In 1946 Prime Minister Mackenzie King renamed it Mount Eisenhower before the General’s visit; the change was deeply unpopular. After 30 years of lobbying by the Castle Mountain Committee, the name was restored in 1979. The eastern pinnacle was designated Eisenhower Tower as a compromise.

Castle Mountain Internment Camp (1915–1917). The largest First World War internment camp in the Rockies held Ukrainian, Austrian, and Hungarian immigrants under the War Measures Act. Internees performed forced labour; building the Banff–Windermere Highway (Highway 93 South), clearing trails, and constructing park infrastructure. A bronze statue “Why?” near the site (Highway 1A) commemorates those confined.

Recreation. Castle Mountain Lookout (7.4 km round trip, ~550 m gain) ascends to an old fire lookout. Brewer’s Buttress (12-pitch, 5.6) is a classic route on Eldon carbonate; Eisenhower Tower via the Dragon’s Back is a mountaineer’s route. Best photographed at sunset from Castle Junction Bridge, when alpenglow turns the limestone orange and red.