Neosho River vs river

Neosho River and river both are nouns.

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

Neosho River (noun)	river (noun)
a river that rises in eastern Kansas and flows eastward into Oklahoma to become a tributary of the Arkansas River	a large natural stream of water (larger than a creek)