The Neacola Mountains in the north central part of the park are the southern most extension of the Alaska Range. The Alaska Range extends far north of the park boundary and includes Mt. McKinley, the tallest mountain in North America and the heart of Denali National Park. The Chigmit Mountains in the south and west part of the park are part of the Aleutian Range, which contains dozens of volcanoes and extends out the Aleutian Islands.