Home Postcode finder QLD Mount Mellum Mount Mellum postcode QLD Mount Mellum is a locality in Queensland covered by postcode 4550. Postcode 4550 State or territory Queensland (QLD) Region Sunshine Coast Add a free Mount Mellum business listing Be the first listing in Mount Mellum Common questionsWhat is the postcode for Mount Mellum?Mount Mellum, QLD has the postcode 4550.What state is Mount Mellum in?Mount Mellum is in Queensland (QLD).Does postcode 4550 cover more than one suburb?Yes. Postcode 4550 covers 2 localities, so the postcode alone does not identify Mount Mellum. Browse other postcodes in Queensland, or widen the search to every Australian postcode.