East Fork Toklat glacier, one of the many smaller glaciers visible from the Denali park road.

Glaciers cover one million acres, or one-sixth of Denali National Park. Like the many arms of an octopus, glaciers flow away from the mountains transporting hundreds of thousand of tons of ice each year. This ice eventually melts in the lower reaches of the glaciers and rapidly fills rivers with turbulent muddy water that flows into the oceans. The most massive glaciers in the park drain snow and ice from the flanks of Mount McKinley. Glaciers play an important part in the development of the landscape of Denali National Park and Preserve.

Hundreds of unnamed glaciers and at least 40 named glaciers flow from heights as high as 19,000 feet and descend to elevations as low as 800 feet above sea level. The Peters Glacier flows from the north and northwest portion of the mountain, whereas the Kahiltna Glacier is situated on the southwestern side of Mount McKinley and shares the southern slopes with an arm of the Ruth Glacier. The Ruth Glacier primarily occupies the southeast side Mount McKinley. From the very top of the mountain, Harper Glacier dumps snow and ice into the upper reaches of Muldrow Glacier, which carries snow and ice off Mount McKinley’s northeast slopes. Of these glacial systems, the Ruth, Kahiltna and Muldrow Glaciers are the longest glaciers in the park; each is more than 30 miles long. The Kahiltna Glacier, which is not only the longest glacier in the park but also in the entire Alaska Range, is 44 miles in length.