Home Postcode finder SA Mount Benson Mount Benson postcode SA Mount Benson is a locality in South Australia covered by postcode 5275. Postcode 5275 State or territory South Australia (SA) Region SA Outer Suburbs Add a free Mount Benson business listing Be the first listing in Mount Benson Common questionsWhat is the postcode for Mount Benson?Mount Benson, SA has the postcode 5275.What state is Mount Benson in?Mount Benson is in South Australia (SA).Does postcode 5275 cover more than one suburb?Yes. Postcode 5275 covers 15 localities, so the postcode alone does not identify Mount Benson. Browse other postcodes in South Australia, or widen the search to every Australian postcode.