Home Postcode finder SA Redhill Redhill postcode SA Redhill is a locality in South Australia covered by postcode 5521. Postcode 5521 State or territory South Australia (SA) Region Sa Subs Near 1 Add a free Redhill business listing Be the first listing in Redhill Common questionsWhat is the postcode for Redhill?Redhill, SA has the postcode 5521.What state is Redhill in?Redhill is in South Australia (SA).Does postcode 5521 cover more than one suburb?No. Postcode 5521 covers Redhill only, which is unusual - most Australian postcodes cover several localities. Browse other postcodes in South Australia, or widen the search to every Australian postcode.