It contains a large part of the Ribeira de Iguape River valley, from which it takes its name, as well as the coastal Iguape-Cananéia-Paranaguá estuary lagoon complex.

[1] Sub-basins of the Ribeira de Iguape River in São Paulo are:[2] Coastal basins of the Iguape-Cananéia-Paranaguá estuary lagoon complex are:[2] The region has over 10,000 species of flora and fauna.

[1] In 1999 the Southeast Atlantic Forest Reserve, which covered 17 municipalities in the Vale do Ribeira, was one of six regions in Brazil that were considered by UNESCO to be natural World Heritage Sites.

[1] Preserved areas are found outside the conservation units in indigenous territories, quilombos and rural districts whose inhabitants practice small-scale subsistence agriculture.

Endemic species include saw-billed hermit (Ramphodon naevius), Guiana dolphin (Sotalia guianensis), yellow-legged tinamou (Crypturellus noctivagus) and the Superagui lion tamarin (Leontopithecus caissara).

[1] The Vale do Ribeira today has large numbers of small properties, up to 50 hectares (120 acres), producing bananas, beef, tomatoes and tangerines.

There are about 80 caiçaras communities along the 140 kilometres (87 mi) Iguape-Cananéia-Paranaguá estuary lagoon complex, mainly engaged in sustainable subsistence artisanal fishing or collection of crustaceans.

Some of the main attractions are the impressive calcareous caves such as those of Diabo, Santana, Morro Preto, Água Suja and Casa da Pedra.