geographic region vs southwestern United States

geographic region and southwestern United States both are nouns.

Word	Noun	Adjective	Verb	Adverb
geographic region	Yes	No	No	No
southwestern United States	Yes	No	No	No

geographic region (noun)	southwestern United States (noun)
a demarcated area of the Earth	the southwestern region of the United States generally including New Mexico, Arizona, Texas, California, and sometimes Utah and Colorado