Mt. McKinley vs McKinley

Mt. McKinley and McKinley both are nouns.

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

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

Mt. McKinley and McKinley: a mountain in south central Alaska; the highest peak in North America (20,300 feet high)

Other synonyms of Mt. McKinley include Denali, Mount McKinley.

Mt. McKinley (noun)	McKinley (noun)
a mountain in south central Alaska; the highest peak in North America (20,300 feet high)	a mountain in south central Alaska; the highest peak in North America (20,300 feet high)
	25th President of the United States; was assassinated by an anarchist (1843-1901)