Willamette River vs river

Willamette River and river both are nouns.

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

Willamette River (noun)	river (noun)
a river in western Oregon that flows north into the Columbia River near Portland	a large natural stream of water (larger than a creek)