Home Postcode finder WA Mount Holland Mount Holland postcode WA Mount Holland 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 Holland business listing Be the first listing in Mount Holland Common questionsWhat is the postcode for Mount Holland?Mount Holland, WA has the postcode 6426.What state is Mount Holland in?Mount Holland 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 Holland. Browse other postcodes in Western Australia, or widen the search to every Australian postcode.