Hawaii is the site of dozens of volcanoes. Most of them are extinct, but a few are very active. The two volcanoes under this paragraph have many vents - places where it can erupt - as do many other Hawaiian volcanoes. Mauna Loa is the largest volcano in Hawaii, and the entire world. It is one of the most active volcanoes in the world. Kilauea is the youngest volcano in all of the Island of Hawaii. It is also one of the most active volcanoes in the world.