Home Postcodes by state SA 5051 Postcode 5051 5051 is the postcode for 4 localities in SA: Blackwood, Coromandel Valley, Craigburn Farm and Hawthorndene. Localities with postcode 5051BlackwoodSACoromandel ValleySACraigburn FarmSAHawthorndeneSA Postcode 5051 State or territory South Australia (SA) Localities 4 Council area Mitcham; Mainly Onkaparinga, partly Mitcham Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 5050 · Postcode 5052