Home Postcodes by state WA 6461 Postcode 6461 6461 is the postcode for 2 localities in WA: Dowerin and Koomberkine. Localities with postcode 6461DowerinWAKoomberkineWA Postcode 6461 State or territory Western Australia (WA) Localities 2 Council area Dowerin Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 6460 · Postcode 6462