Home Postcode finder WA Deanmill Deanmill postcode WA Deanmill is a locality in Western Australia covered by postcode 6258. Postcode 6258 State or territory Western Australia (WA) Region Wa Subs 3 Sth Rd Add a free Deanmill business listing Be the first listing in Deanmill Common questionsWhat is the postcode for Deanmill?Deanmill, WA has the postcode 6258.What state is Deanmill in?Deanmill is in Western Australia (WA).Does postcode 6258 cover more than one suburb?Yes. Postcode 6258 covers 22 localities, so the postcode alone does not identify Deanmill. Browse other postcodes in Western Australia, or widen the search to every Australian postcode.