Pee Dee River vs river

Pee Dee River and river both are nouns.

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

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