Home Postcode finder WA Mills Lake Mills Lake postcode WA Mills Lake is a locality in Western Australia covered by postcode 6336. Postcode 6336 State or territory Western Australia (WA) Region Wa Subs 2 Gsr Add a free Mills Lake business listing Be the first listing in Mills Lake Common questionsWhat is the postcode for Mills Lake?Mills Lake, WA has the postcode 6336.What state is Mills Lake in?Mills Lake is in Western Australia (WA).Does postcode 6336 cover more than one suburb?Yes. Postcode 6336 covers 6 localities, so the postcode alone does not identify Mills Lake. Browse other postcodes in Western Australia, or widen the search to every Australian postcode.