Established as a game reserve in 1942, the area became a national park in 1972 and was designated a World Heritage site in 1979. The park has an area of 8,500 square miles (22,015 square km), which is dominated by two northwest–southeast-trending parallel mountain systems. The St. Elias Mountains (Saint Elias Mountains) in the southwest reach an elevation of 19,524 feet (5,951 metres) at Mount Logan (Logan, Mount), the highest point in Canada and the second highest peak in North America, in the southwestern corner of the park. These mountains accommodate one of the largest nonpolar ice field systems in the world and include the Steele, Kaskawulsh, and Lowell glaciers. The St. Elias Mountains are separated from the Kluane Range of mountains to the northeast by the valleys and plateaus of the Duke Depression. The Kluane Range, with peaks averaging more than 6,600 feet (2,000 metres) in height, is more densely vegetated and inhabited by more wildlife than much of the rest of the park and is accessible on its eastern slopes from the Alaska Highway.

Montane forest, including spruce, aspen, and poplar, covers much of the park's lower valleys and slopes. Low-growing willow, alder, and dwarf birch are found in the transitional subalpine zone; alpine tundra at higher elevations includes a variety of colourful Arctic flowers. Dall sheep are the park's most numerous large mammal, and a large protected population of grizzly bears live in the park. Other wildlife includes moose, mountain goats, deer, wolves, black bears, caribou, wolverines, ground squirrels, and many species of birds. Researchers in the 1990s catalogued a surprising variety of plant and animal life, including pikas and spiders, on the area's nunataks (crags or peaks surrounded by glaciers). Hiking, rafting on the Alsek River, flying over the Kaskawulsh Glacier, and fishing are popular activities in the park.