Boulder Peak, an 8,533-foot mountain in Glacier National Park’s Livingston Range in Montana, reflects both the park’s glacial and geologic history. Boulder Glacier, a remnant ice body on its northern slopes, connects the peak to a long legacy of ice in the region. The mountain lies in a subarctic climate marked by long, bitterly cold winters, short cool summers, and severe wind chills. Its sedimentary rocks were deposited from the Precambrian through the Jurassic in ancient shallow seas. Boulder Peak’s structure also formed within the Lewis Overthrust, when much older Precambrian rock was thrust over younger Cretaceous rock about 170 million years ago.