The Castle Mountains, highest point Elk Peak, el.

8,589 feet (2,618 m),[1] are an island range east of White Sulphur Springs in Meagher County, Montana, United States.

[3] The western portion of the Castles are moist, while the eastside is dry, porous limestone hills.

[3] The range gets its name from "castle turrets", 50-foot high igneous rock spires on the western slopes.

[3] The range was the focus of mining activity in the previous century; crumbling remains of old miners' cabins and diggings are present throughout the area.