Red River of the South vs Texas

Red River of the South and Texas both are nouns.

Word	Noun	Adjective	Verb	Adverb
Red River of the South	Yes	No	No	No
Texas	Yes	No	No	No

Red River of the South (noun)	Texas (noun)
a tributary of the Mississippi River that flows eastward from Texas along the southern boundary of Oklahoma and through Louisiana	the second largest state; located in southwestern United States on the Gulf of Mexico