Rushmore vs Mt. Rushmore

Rushmore and Mt. Rushmore both are nouns.

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

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

Rushmore and Mt. 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 Rushmore include Mount Rushmore.

Rushmore (noun)	Mt. 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