river vs Pee Dee River

river and Pee Dee River both are nouns.

Word	Noun	Adjective	Verb	Adverb
river	Yes	No	No	No
Pee Dee River	Yes	No	No	No

river (noun)	Pee Dee River (noun)
a large natural stream of water (larger than a creek)	a river that flows through central North Carolina and northeastern South Carolina to the Atlantic Ocean