Department of the Interior vs Interior Department

Department of the Interior and Interior Department both are nouns.

Word	Noun	Adjective	Verb	Adverb
Department of the Interior	Yes	No	No	No
Interior Department	Yes	No	No	No

As nouns, Department of the Interior and Interior Department are synonyms defined as:

Department of the Interior and Interior Department: the United States federal department charged with conservation and the development of natural resources; created in 1849

Other synonyms of Department of the Interior include DoI, Interior.

Department of the Interior (noun)	Interior Department (noun)
the United States federal department charged with conservation and the development of natural resources; created in 1849	the United States federal department charged with conservation and the development of natural resources; created in 1849