Home Postcodes by state QLD 4419 Postcode 4419 4419 is the postcode for 3 localities in QLD: Cockatoo, Grosmont and Wandoan. Localities with postcode 4419CockatooQLDGrosmontQLDWandoanQLD Postcode 4419 State or territory Queensland (QLD) Localities 3 Council area Banana; Western Downs Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 4418 · Postcode 4420