Mississippi River vs U.S.A.

Mississippi River and U.S.A. both are nouns.

Word	Noun	Adjective	Verb	Adverb
Mississippi River	Yes	No	No	No
U.S.A.	Yes	No	No	No

Mississippi River (noun)	U.S.A. (noun)
a major North American river and the chief river of the United States; rises in northern Minnesota and flows southward into the Gulf of Mexico	North American republic containing 50 states - 48 conterminous states in North America plus Alaska in northwest North America and the Hawaiian Islands in the Pacific Ocean; achieved independence in 1776