Home Postcodes by state QLD 4301 Postcode 4301 4301 is the postcode for 3 localities in QLD: Collingwood Park, Redbank and Redbank Plains. Localities with postcode 4301Collingwood ParkQLDRedbankQLDRedbank PlainsQLD Postcode 4301 State or territory Queensland (QLD) Localities 3 Council area Ipswich Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 4300 · Postcode 4303