Lagoa do Fogo is one of the largest of the waterbodies in the Azores, and occupies the central caldera of the Água de Pau Massif, in the central area of the island of São Miguel. The caldera is the youngest volcano on the island of São Miguel, formed approximately 15 000 years ago, resulting from the collapse at the top of the volcano, some 5000 years ago. The last eruption occurred in 1563. It falls within the borders of the civil parishes of Conceição, Matriz and Água de Alto, in the municipalities of Ribeira Grande and Vila Franca do Campo, respectively.