river vs Clinch River

river and Clinch River both are nouns.

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

river (noun)	Clinch River (noun)
a large natural stream of water (larger than a creek)	a river that rises in southwestern Virginia and flows generally southwestward across eastern Tennessee to the Tennessee River