Angara River vs Upper Tunguska

Angara River and Upper Tunguska both are nouns.

Word	Noun	Adjective	Verb	Adverb
Angara River	Yes	No	No	No
Upper Tunguska	Yes	No	No	No

As nouns, Angara River and Upper Tunguska are synonyms defined as:

Angara River and Upper Tunguska: a river in southeastern Siberia that flows northwest from Lake Baikal to become a tributary of the Yenisei River

Other synonyms of Angara River include Angara, Tunguska.

Angara River (noun)	Upper Tunguska (noun)
a river in southeastern Siberia that flows northwest from Lake Baikal to become a tributary of the Yenisei River	a river in southeastern Siberia that flows northwest from Lake Baikal to become a tributary of the Yenisei River