Anglesea Island vs Anglesey

Anglesea Island and Anglesey both are nouns.

Word	Noun	Adjective	Verb	Adverb
Anglesea Island	Yes	No	No	No
Anglesey	Yes	No	No	No

As nouns, Anglesea Island and Anglesey are synonyms defined as:

Other synonyms of Anglesea Island include Anglesea, Anglesey Island, Mona.

Anglesea Island (noun)	Anglesey (noun)
an island to the northwest of Wales	an island to the northwest of Wales