Lower Peninsula vs Lower Peninsula of Michigan

Lower Peninsula and Lower Peninsula of Michigan both are nouns.

Word	Noun	Adjective	Verb	Adverb
Lower Peninsula	Yes	No	No	No
Lower Peninsula of Michigan	Yes	No	No	No

As nouns, Lower Peninsula and Lower Peninsula of Michigan are synonyms defined as:

Lower Peninsula and Lower Peninsula of Michigan: the part of Michigan between Lake Michigan and Lake Huron

Lower Peninsula (noun)	Lower Peninsula of Michigan (noun)
the part of Michigan between Lake Michigan and Lake Huron	the part of Michigan between Lake Michigan and Lake Huron