Home Postcode finder QLD Mount Hallen Mount Hallen postcode QLD Mount Hallen is a locality in Queensland covered by postcode 4312. Postcode 4312 State or territory Queensland (QLD) Region Western Suburbs Add a free Mount Hallen business listing Be the first listing in Mount Hallen Common questionsWhat is the postcode for Mount Hallen?Mount Hallen, QLD has the postcode 4312.What state is Mount Hallen in?Mount Hallen is in Queensland (QLD).Does postcode 4312 cover more than one suburb?Yes. Postcode 4312 covers 13 localities, so the postcode alone does not identify Mount Hallen. Browse other postcodes in Queensland, or widen the search to every Australian postcode.