Home Postcodes by state WA 6646 Postcode 6646 6646 is the postcode for 3 localities in WA: Lake Carnegie, Little Sandy Desert and Wiluna. Localities with postcode 6646Lake CarnegieWALittle Sandy DesertWAWilunaWA Postcode 6646 State or territory Western Australia (WA) Localities 3 Council area Wiluna Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 6642 · Postcode 6701