river vs Detroit River

river and Detroit River both are nouns.

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

river (noun)	Detroit River (noun)
a large natural stream of water (larger than a creek)	a short river flowing from Lake St. Clair to Lake Erie along the border between the United States and Canada; one the busiest inland waterways in the world