Home Postcodes by state WA 6445 Postcode 6445 6445 is the postcode for 2 localities in WA: North Cascade and Salmon Gums. Localities with postcode 6445North CascadeWASalmon GumsWA Postcode 6445 State or territory Western Australia (WA) Localities 2 Council area Esperance Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 6443 · Postcode 6446