Iriri River Iriri River The Iriri River () is a large tributary of the Xingu River in Brazil, in the state of Pará. It is long making it the 116th longest river in the world (with Krishna River, India) and the 15th longest in the Amazon basin. The headwaters are the traditional home of the Panará people. The river rises in the Nascentes da Serra do Cachimbo Biological Reserve, a strictly protected conservation unit established in 2005 in the Serra do Cachimbo. It is one of the headwaters of the Xingu River. It flows for before joining the Xingu, running through the
Xingu Indigenous Park April. The headwaters of the Xingu River are in the south of the park. The area covered by the park was defined in 1961 and covers parts of the municipalities of Canarana, Paranatinga, São Félix do Araguaia, São José do Xingu, Gaúcha do Norte, Feliz Natal, Querência, União do Sul, Nova Ubiratã and Marcelândia in the state of Mato Grosso. The national park was created after a campaign by the Villas-Bôas brothers for protection of the region. An account of the exploration of this area by the Villas-Bôas brothers and their efforts to protect the region is documented in the