Home Postcodes by state NSW 2079 Postcode 2079 2079 is the postcode for Mount Colah, NSW. Localities with postcode 2079Mount ColahNSW Postcode 2079 State or territory New South Wales (NSW) Localities 1 Council area Hornsby Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 2077 · Postcode 2080