Colorado vs South Platte

Colorado and South Platte both are nouns.

Word	Noun	Adjective	Verb	Adverb
Colorado	Yes	No	No	No
South Platte	Yes	No	No	No

Colorado (noun)	South Platte (noun)
a state in west central United States in the Rocky Mountains	a tributary of the Platte River
an important river in the southwestern United States; rises in the Rocky Mountains of northern Colorado and flows southwest through Utah into Arizona (where it flows through the Grand Canyon) and then southward through the southern tip of Nevada, then forming the border between California and Arizona and finally into Mexico where it empties into the Gulf of California; the main source of water in the southwestern United States
a river in Texas; flows southeast into the Gulf of Mexico