Home Postcodes by state WA 6556 Postcode 6556 6556 is the postcode for 5 localities in WA: Beechina, Chidlow, Gorrie, Malmalling and The Lakes. Localities with postcode 6556BeechinaWAChidlowWAGorrieWAMalmallingWAThe LakesWA Postcode 6556 State or territory Western Australia (WA) Localities 5 Council area Mundaring Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 6537 · Postcode 6558