Black Hills vs mountain range

Black Hills and mountain range both are nouns.

Word	Noun	Adjective	Verb	Adverb
Black Hills	Yes	No	No	No
mountain range	Yes	No	No	No

Black Hills (noun)	mountain range (noun)
mountains in southwestern South Dakota and northeastern Wyoming; sacred to the Sioux (whites settling in the Black Hills led to the Battle of Little Bighorn); site of Mount Rushmore	a series of hills or mountains