Home Postcode finder QLD Basalt Basalt postcode QLD Basalt is a locality in Queensland covered by postcode 4820. Postcode 4820 State or territory Queensland (QLD) Region North QLD Add a free Basalt business listing Be the first listing in Basalt Common questionsWhat is the postcode for Basalt?Basalt, QLD has the postcode 4820.What state is Basalt in?Basalt 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 Basalt. Browse other postcodes in Queensland, or widen the search to every Australian postcode.