Department of the Treasury vs United States Treasury

Department of the Treasury and United States Treasury both are nouns.

Word	Noun	Adjective	Verb	Adverb
Department of the Treasury	Yes	No	No	No
United States Treasury	Yes	No	No	No

As nouns, Department of the Treasury and United States Treasury are synonyms defined as:

Department of the Treasury and United States Treasury: the federal department that collects revenue and administers federal finances; the Treasury Department was created in 1789

Other synonyms of Department of the Treasury include Treasury, Treasury Department.

Department of the Treasury (noun)	United States Treasury (noun)
the federal department that collects revenue and administers federal finances; the Treasury Department was created in 1789	the federal department that collects revenue and administers federal finances; the Treasury Department was created in 1789