Yukon River vs Yukon

Yukon River and Yukon both are nouns.

Word	Noun	Adjective	Verb	Adverb
Yukon River	Yes	No	No	No
Yukon	Yes	No	No	No

As nouns, Yukon River and Yukon are synonyms defined as:

Yukon River and Yukon: a North American river that flows westward from the Yukon Territory through central Alaska to the Bering Sea

Yukon River (noun)	Yukon (noun)
a North American river that flows westward from the Yukon Territory through central Alaska to the Bering Sea	a territory in northwestern Canada; site of the Klondike gold rush in the 1890s
	a North American river that flows westward from the Yukon Territory through central Alaska to the Bering Sea