Located northwest of the state of Pará, with an area of 330,000 hectares, this is the largest Conservation Unit in the Tocantins and Xingu interflow. Founded in 1961, it occupies part of the municipalities of Melgaço and Portel and enters the basin of the Anapu river. The lowland dense ombrophilous Forest covers 85% of the area, the rest is covered by igapó (19%) and patches of open vegetation. To date, 1,010 species of plants, 134 species of lichens, 33 species of macroscopic fungi and 746 species of animals have been recorded for Caxiuanã.