Ruth Glacier is a glacier in Denali National Park and Preserve in the U.S. state of Alaska.[1] Its upper reaches are approximately 3 vertical miles below the summit of Denali. The glacier's "Great Gorge" is one mile wide, and drops almost 2,000 feet (610 m) over 10 miles (16 km), with crevasses along the surface. Above the surface on both sides are 4,900 feet (1,500 m) granite cliffs. From the top of the cliffs to the bottom of the glacier is a height exceeding that of the Grand Canyon. Ruth Glacier moves at a rate of 3 feet (0.91 m) per day and was measured to be 4,000 feet (1,200 m) thick in 1983.[2]