Home Postcodes by state WA Mount Palmer Mount Palmer postcode WA Mount Palmer is a locality in Western Australia covered by postcode 6426. Postcode 6426 State or territory Western Australia (WA) Region Wa Subs 1 G Flds Add a free Mount Palmer business listing Be the first listing in Mount Palmer Common questionsWhat is the postcode for Mount Palmer?Mount Palmer, WA has the postcode 6426.What state is Mount Palmer in?Mount Palmer is in Western Australia (WA).Does postcode 6426 cover more than one suburb?Yes. Postcode 6426 covers 14 localities, so the postcode alone does not identify Mount Palmer. Browse other postcodes in Western Australia, or widen the search to every Australian postcode.