Saint Lawrence River vs St. Lawrence River

Saint Lawrence River and St. Lawrence River both are nouns.

Word	Noun	Adjective	Verb	Adverb
Saint Lawrence River	Yes	No	No	No
St. Lawrence River	Yes	No	No	No

As nouns, Saint Lawrence River and St. Lawrence River are synonyms defined as:

Saint Lawrence River and St. Lawrence River: a North American river; flows into the Gulf of Saint Lawrence and the North Atlantic

Other synonyms of Saint Lawrence River include Saint Lawrence, St. Lawrence.

Saint Lawrence River (noun)	St. Lawrence River (noun)
a North American river; flows into the Gulf of Saint Lawrence and the North Atlantic	a North American river; flows into the Gulf of Saint Lawrence and the North Atlantic