Yunaska Island, Alaska

Yunaskais an uninhabited island which is the largest of the Islands of Four Mountains group in the Aleutian Islands of southwestern Alaska, United States. It has a land area of 66.834 square miles (173.099 square kilometres)

The island comprises two volcanic mountains, with a valley between. The western mountain is composed of four overlapping and eroded stratovolcanoes, with a cinder cone field at the western end. It has not been historically active. The eastern mountain is a large shield volcano with two overlapping summit calderas, which last erupted in 1937.