Amphitheater Mountain is an 8,695-foot peak in the Lewis Range of Glacier National Park in Montana. Its English name refers to a form likened to a Greek amphitheater. The mountain also bears a Blackfoot name, given as Three Horns or Niuóxkai-ozkina, tied to a Blackfoot warrior remembered in a story about capturing a Nez Perce woman and then living happily ever after. It has also been known as Whalen Mountain, named for a former park ranger. The mountain remains one of the named peaks in Glacier National Park’s rugged alpine landscape.