Amazon river dolphin widespread river dolphins. They are present in six countries in South America: Bolivia, Brazil, Colombia, Ecuador, Peru, and Venezuela, in an area covering about . The boundaries are set by waterfalls, such as the Xingu and Tapajós rivers in Brazil, as well as very shallow water. A series of rapids and waterfalls in the Madeira River have isolated one population, recognized as the subspecies "I. g. boliviensis", in the southern part of the Amazon basin in Bolivia. They are also distributed in the basin of the Orinoco River, except the Caroni River and the upper Caura River in Venezuela. The
Tapajós-Xingu moist forests from other moist forest areas. There are urban centers at Santarém at the mouth of the Tapajós, Aveiro on the lower Tapajós and Altamira on the Iriri River. The ecoregion is crossed by the Trans-Amazonian Highway (BR-230) and the BR-163 highway from Santarém to Cuiabá. To the northwest the ecoregion adjoins the Madeira-Tapajós moist forests on the other side of the Tapajós River. To the north it adjoins the Gurupa várzea along the Amazon River. The Uatuma-Trombetas moist forests are on the opposite bank of the Amazon. To the east are the Xingu-Tocantins-Araguaia moist forests. To the south and southwest