Home Postcodes by state SA 5158 Postcode 5158 5158 is the postcode for 4 localities in SA: Hallett Cove, O'Halloran Hill, Sheidow Park and Trott Park. Localities with postcode 5158Hallett CoveSAO'Halloran HillSASheidow ParkSATrott ParkSA Postcode 5158 State or territory South Australia (SA) Localities 4 Council area Marion; Mainly Onkaparinga, partly Marion Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 5157 · Postcode 5159