Congress vs U.S. Congress

Congress and U.S. Congress both are nouns.

Word	Noun	Adjective	Verb	Adverb
Congress	Yes	No	No	No
U.S. Congress	Yes	No	No	No

As nouns, Congress and U.S. Congress are synonyms defined as:

Congress and U.S. Congress: the legislature of the United States government

Other synonyms of Congress include United States Congress, US Congress.

Congress (noun)	U.S. Congress (noun)
the legislature of the United States government	the legislature of the United States government