river vs St. Johns River

river and St. Johns River both are nouns.

Word	Noun	Adjective	Verb	Adverb
river	Yes	No	No	No
St. Johns River	Yes	No	No	No

river (noun)	St. Johns River (noun)
a large natural stream of water (larger than a creek)	a river in northeastern Florida that flows northward to Jacksonville and then eastward to empty into the Atlantic Ocean