Home Postcodes by state QLD 4878 Postcode 4878 4878 is the postcode for 6 localities in QLD: Barron, Caravonica, Holloways Beach, Machans Beach, Smithfield and Yorkeys Knob. Localities with postcode 4878BarronQLDCaravonicaQLDHolloways BeachQLDMachans BeachQLDSmithfieldQLDYorkeys KnobQLD Postcode 4878 State or territory Queensland (QLD) Localities 6 Council area Cairns Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 4877 · Postcode 4879