The Caverna do Diabo State Park is divided between the municipalities of Barra do Turvo, Cajati, Eldorado and Iporanga in São Paulo.

[3] The park forms part of the Serra de Paranapiacaba Mosaic, which has over 120,000 hectares (300,000 acres) and contains the largest remaining area of Atlantic Forest in Brazil.

[4] The Caverna do Diabo State Park is in a region that contains mixed rainforests and typical Atlantic Forest, with areas of araucaria.

There are many species of fauna with a high degree of endemism, including birds, small mammals, reptiles, amphibians and insects.

It follows an underground stretch of the Rio das Ostras in the Serra de André Lopes, and is over 5 kilometres (3.1 mi) long.