Home Postcode finder QLD Irongate Irongate postcode QLD Irongate is a locality in Queensland covered by postcode 4356. Postcode 4356 State or territory Queensland (QLD) Region Toowoomba Region Add a free Irongate business listing Be the first listing in Irongate Common questionsWhat is the postcode for Irongate?Irongate, QLD has the postcode 4356.What state is Irongate in?Irongate is in Queensland (QLD).Does postcode 4356 cover more than one suburb?Yes. Postcode 4356 covers 18 localities, so the postcode alone does not identify Irongate. Browse other postcodes in Queensland, or widen the search to every Australian postcode.