Tocantins river, 1,640 mi (2,639 km) long, formed in S central Goiás state, Brazil, by the confluence of two headstreams. It flows N to the Pará River, the southern distributary of the Amazon, SW of Belém. It is only partly navigable because of rapids. There are diamond washes near Carolina. The main tributary is the Araguaía.

Tocantins (tŏŏkəntēns´), state (1996 pop. 1,048,514), 110,700 sq mi (286,787 sq km), N central Brazil. Palmas is the capital. Created in 1988 from the northern half of Goiás state, Tocantins is in the Brazilian Highlands and is drained by the Araguaia and Tocantins rivers. It is a developing area with a large indigenous population and abundant mineral resources.