Baja California vs Baja California Peninsula

Baja California and Baja California Peninsula both are nouns.

Word	Noun	Adjective	Verb	Adverb
Baja California	Yes	No	No	No
Baja California Peninsula	Yes	No	No	No

As nouns, Baja California and Baja California Peninsula are synonyms defined as:

Baja California and Baja California Peninsula: a mountainous peninsula on northwest Mexico

Other synonyms of Baja California include Lower California.

Baja California (noun)	Baja California Peninsula (noun)
a mountainous peninsula on northwest Mexico	a mountainous peninsula on northwest Mexico