Denali National Park and Preserve covers 2.4 million hectares (6 million acres), most of it only accessible by foot, dogsled, or aircraft. One road provides vehicular access, mainly during the summer season. The landscape is not static, as landslides, braided rivers of glacial melt, and moving glaciers attest. There are also human impacts on the land, such as changes in air quality (airborne contaminants) and climate.
Near the geographic center of Alaska, the park surrounds Denali (formerly Mt. McKinley), which hinges the great arc of the Alaska Range mountains. The Alaska Range is a barrier to air movements and precipitation from maritime influences to the south, thus creating a transitional climate. Areas on the south side of the range are significantly wetter, with twice the precipitation of the north side. Temperatures on the south side of the range have less variation and tend to be warmer in winter and cooler in summer, due to more maritime influences. North of the Alaska Range, a continental climate prevails.