Upper Avon River vs Upper Avon

Upper Avon River and Upper Avon both are nouns.

Word	Noun	Adjective	Verb	Adverb
Upper Avon River	Yes	No	No	No
Upper Avon	Yes	No	No	No

As nouns, Upper Avon River and Upper Avon are synonyms defined as:

Upper Avon River and Upper Avon: a river in central England that flows through Stratford-on-Avon and empties into the Severn

Other synonyms of Upper Avon River include Avon, River Avon.

Upper Avon River (noun)	Upper Avon (noun)
a river in central England that flows through Stratford-on-Avon and empties into the Severn	a river in central England that flows through Stratford-on-Avon and empties into the Severn