The Tocantins basin, or Araguaia-Tocantins basin, is a Brazilian river basin, almost entirely located between the 2ºS and 18ºS parallels and the 46ºW and 56ºW meridians. The main rivers in the basin are Tocantins and Araguaia.[1]
The basin extends to the states of Tocantins and Goiás (58%), Mato Grosso (24%), Pará (13%), Maranhão (4%), in addition to the Federal District (1%). It is the largest hydrographic basin entirely Brazilian.[2]
For water resource management purposes, it is inserted in the Tocantins-Araguaia hydrographic region.[2]