Home Postcode finder QLD Millchester Millchester postcode QLD Millchester is a locality in Queensland covered by postcode 4820. Postcode 4820 State or territory Queensland (QLD) Region North QLD Add a free Millchester business listing Be the first listing in Millchester Common questionsWhat is the postcode for Millchester?Millchester, QLD has the postcode 4820.What state is Millchester in?Millchester is in Queensland (QLD).Does postcode 4820 cover more than one suburb?Yes. Postcode 4820 covers 21 localities, so the postcode alone does not identify Millchester. Browse other postcodes in Queensland, or widen the search to every Australian postcode.