The Site is located on the Marajó archipelago, the world’s largest fluvial-maritime archipelago, at the mouth of the Amazon River. It consists of a corridor of 23 conservation units with a combined area of over 3.8 million hectares. On this stretch of coast lies one of the biggest continuous mangrove formations in the world; with over 8,900 square kilometres stretching over 700 km, it holds 70% of the mangroves of Brazil. The Site is adjacent to other Ramsar Sites: Cabo Orange, Baixada Maranhense, Reentrancias Maranhenses and Parcel Manuel Luiz. The Site and the wider Amazon estuary and coastal basins ecoregion are extremely biodiverse and of great international importance. Around 40 species found in the Site are both nationally and globally threatened, and 21 more listed as threatened on Brazil’s Red List. Marine, freshwater and terrestrial species including mammals, reptiles, birds and fish are included among these.