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 peoples European slavers arrived in the Xingu region around 1750. Xinuguano population was estimated in the tens of thousands but was dramatically reduced by diseases and slavery by Europeans. In the centuries since the penetration of the Europeans into South America, the Xingu fled from different regions to escape modernization and cultural assimilation. Nonetheless settlers made it up as far as the upper run of the Rio Xingu. By the end of the 19th century, about 3,000 natives lived at the Alto Xingu, where their current political status has kept them protected against European intruders. By the mid twentieth century this