river vs North Platte

river and North Platte both are nouns.

Word	Noun	Adjective	Verb	Adverb
river	Yes	No	No	No
North Platte	Yes	No	No	No

river (noun)	North Platte (noun)
a large natural stream of water (larger than a creek)	a town in west central Nebraska on the Platte River
	a river that rises in northern Colorado and flows northward into Wyoming and then eastward and southeastward through Nebraska where it joins the South Platte to form the Platte River