Kissimmee River vs river

Kissimmee River and river both are nouns.

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

Kissimmee River (noun)	river (noun)
a river of central Florida that flows southward to Lake Okeechobee	a large natural stream of water (larger than a creek)