Home Postcode finder SA Mount Barker Summit Mount Barker Summit postcode SA Mount Barker Summit is a locality in South Australia covered by postcode 5251. Postcode 5251 State or territory South Australia (SA) Region Sa Subs Near 2 Add a free Mount Barker Summit business listing Be the first listing in Mount Barker Summit Common questionsWhat is the postcode for Mount Barker Summit?Mount Barker Summit, SA has the postcode 5251.What state is Mount Barker Summit in?Mount Barker Summit is in South Australia (SA).Does postcode 5251 cover more than one suburb?Yes. Postcode 5251 covers 6 localities, so the postcode alone does not identify Mount Barker Summit. Browse other postcodes in South Australia, or widen the search to every Australian postcode.