Vistula River vs river

Vistula River and river both are nouns.

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

Vistula River (noun)	river (noun)
the longest and largest river in Poland; flows into the Baltic Sea	a large natural stream of water (larger than a creek)