Mount Helen is an 8,538-foot mountain in Glacier National Park’s Lewis Range, rising prominently above Upper Two Medicine Lake in the park’s southeastern area. The Continental Divide crosses its summit, giving it a notable place in the Two Medicine landscape. Like many peaks in the park, it consists of sedimentary rock laid down in ancient shallow seas from the Precambrian to the Jurassic. Its broader mountain setting was formed by the Lewis Overthrust, which began about 170 million years ago when a massive slab of older rock was pushed over younger Cretaceous rock. Mount Helen lies in an alpine subarctic climate with severe winters and short summers.