Home Postcode finder QLD Cornwall Cornwall postcode QLD Cornwall is a locality in Queensland covered by postcode 4455. Postcode 4455 State or territory Queensland (QLD) Region Toowoomba Region Add a free Cornwall business listing Be the first listing in Cornwall Common questionsWhat is the postcode for Cornwall?Cornwall, QLD has the postcode 4455.What state is Cornwall in?Cornwall is in Queensland (QLD).Does postcode 4455 cover more than one suburb?Yes. Postcode 4455 covers 19 localities, so the postcode alone does not identify Cornwall. Browse other postcodes in Queensland, or widen the search to every Australian postcode.