Home Postcode finder NSW Mount Vernon Mount Vernon postcode NSW Mount Vernon is a locality in New South Wales covered by postcode 2178. Postcode 2178 State or territory New South Wales (NSW) Region Ingleburn Add a free Mount Vernon business listing Be the first listing in Mount Vernon Common questionsWhat is the postcode for Mount Vernon?Mount Vernon, NSW has the postcode 2178.What state is Mount Vernon in?Mount Vernon is in New South Wales (NSW).Does postcode 2178 cover more than one suburb?Yes. Postcode 2178 covers 3 localities, so the postcode alone does not identify Mount Vernon. Browse other postcodes in New South Wales, or widen the search to every Australian postcode.