Home Postcode finder WA Lake Muir Lake Muir postcode WA Lake Muir 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 Lake Muir business listing Be the first listing in Lake Muir Common questionsWhat is the postcode for Lake Muir?Lake Muir, WA has the postcode 6258.What state is Lake Muir in?Lake Muir 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 Lake Muir. Browse other postcodes in Western Australia, or widen the search to every Australian postcode.