Home Postcode finder VIC Mountain Gate Mountain Gate postcode VIC Mountain Gate is a locality in Victoria covered by postcode 3156. Postcode 3156 State or territory Victoria (VIC) Region Ferntree Gully Add a free Mountain Gate business listing Be the first listing in Mountain Gate Common questionsWhat is the postcode for Mountain Gate?Mountain Gate, VIC has the postcode 3156.What state is Mountain Gate in?Mountain Gate is in Victoria (VIC).Does postcode 3156 cover more than one suburb?Yes. Postcode 3156 covers 5 localities, so the postcode alone does not identify Mountain Gate. Browse other postcodes in Victoria, or widen the search to every Australian postcode.