Which is the largest dormant volcano in the world?

Haleakalā or the East Maui Volcano, is a massive shield volcano that forms more than 75% of the Hawaiian Island of Maui. The western 25% of the island is formed by another volcano, Mauna Kahalawai, also referred to as the West Maui Mountains.

Until recently, East Maui Volcano was thought to have last erupted around 1790, based largely on comparisons of maps made during the voyages of La Perouse and George Vancouver. Recent advanced dating tests, however, have shown that the last eruption was more likely to have been in the 17th century. These last flows from the southwest rift zone of Haleakalā make up the large lava deposits of the Ahihi Kina`u/La Perouse Bay area of South Maui.