Home Postcodes by state WA 6431 Postcode 6431 6431 is the postcode for 13 localities in WA: Boorara, Brown Hill, Bulong, Emu Flat, Feysville, Kanowna and 7 more. Localities with postcode 6431BooraraWABrown HillWABulongWAEmu FlatWAFeysvilleWAKanownaWAKookynieWAKurnalpiWALakewoodWAOra BandaWAPlumridge LakesWATrafalgarWAWarburtonWA Postcode 6431 State or territory Western Australia (WA) Localities 13 Council area Kalgoorlie-Boulder; Menzies; Ngaanyatjarraku Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 6430 · Postcode 6432