Home Postcodes by state WA 6109 Postcode 6109 6109 is the postcode for 2 localities in WA: Maddington and Orange Grove. Localities with postcode 6109MaddingtonWAOrange GroveWA Postcode 6109 State or territory Western Australia (WA) Localities 2 Council area Gosnells Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 6108 · Postcode 6110