Lagoa do Caiado is the largest lagoon on Pico Island, Azores. The high-altitude lagoon is located on the Achada Plateau, an extensive volcanic mountain range covering most of the central area of the island. The waters are clear and are used for public supply since 1993. The lagoon is located within the Partial Natural Forest Reserve of Lagoa do Caiado; the Special Conservation Zone of Mount Pico, Prainha and Caveiro; the Special Protection Zone of the Central Zone of Pico; and the Geopark of the Achada Plateu.