Home Postcode finder SA Hornsdale Hornsdale postcode SA Hornsdale is a locality in South Australia covered by postcode 5491. Postcode 5491 State or territory South Australia (SA) Region SA Outer Suburbs Add a free Hornsdale business listing Be the first listing in Hornsdale Common questionsWhat is the postcode for Hornsdale?Hornsdale, SA has the postcode 5491.What state is Hornsdale in?Hornsdale is in South Australia (SA).Does postcode 5491 cover more than one suburb?Yes. Postcode 5491 covers 7 localities, so the postcode alone does not identify Hornsdale. Browse other postcodes in South Australia, or widen the search to every Australian postcode.