Volcano Island used to be an island in the Nonestic Ocean. The island is inhabited by cooks who use the volcano's heat to make baked goods. A painting of Mombi that came to life went to the island. To defeat her, Ozma, the Wizard of Oz, and Glinda shrank the island down and trapped her inside of it. They brought Mombi and the volcano to Lake Quad, where Jack Pumpkinhead repainted her to be pleasant and pretty instead of evil and ugly. She is still in the volcano, admiring herself. The cooks are also still on the volcano, and they are in charge of baking for the people of the Emerald City. (Lucky Bucky in Oz)
Volcano Island is not to be confused with Salamander Island.