river vs Tocantins River

river and Tocantins River both are nouns.

Word	Noun	Adjective	Verb	Adverb
river	Yes	No	No	No
Tocantins River	Yes	No	No	No

river (noun)	Tocantins River (noun)
a large natural stream of water (larger than a creek)	a river in eastern Brazil that flows generally north to the Para River