Mt. Rushmore vs Mount Rushmore

Mt. Rushmore and Mount Rushmore both are nouns.

Word	Noun	Adjective	Verb	Adverb
Mt. Rushmore	Yes	No	No	No
Mount Rushmore	Yes	No	No	No

As nouns, Mt. Rushmore and Mount Rushmore are synonyms defined as:

Mt. Rushmore and Mount Rushmore: a mountain in the Black Hills of South Dakota; the likenesses of Washington and Jefferson and Lincoln and Roosevelt are carved on it

Other synonyms of Mt. Rushmore include Rushmore.

Mt. Rushmore (noun)	Mount Rushmore (noun)
a mountain in the Black Hills of South Dakota; the likenesses of Washington and Jefferson and Lincoln and Roosevelt are carved on it	a mountain in the Black Hills of South Dakota; the likenesses of Washington and Jefferson and Lincoln and Roosevelt are carved on it