The Island of Hawai'i is the largest of the Hawaiian Islands, and the southernmost. The island is built from seven separate shield volcanoes that errupted somewhat sequentially, one overlapping the other. At least two of these have been buried by more recent volcanoes. These are (from oldest to youngest): Kohala (extinct), Ninole (extinct, mostly buried), Mauna Kea (extinct or dormant?), Hualalai (dormant), Mauna Loa (active), Kulani (extinct, mostly buried), and Kilauea (very active).
Called locally the "Big Island," its area is 4,038 sq. miles. In greatest dimension, the island is 93 miles across. The Big Island represents more than half (~62%) of the total land area of the State of Hawaii and is administered under the County of Hawaii.