Home Postcodes by state NSW 2125 Postcode 2125 2125 is the postcode for West Pennant Hills, NSW. Localities with postcode 2125West Pennant HillsNSW Postcode 2125 State or territory New South Wales (NSW) Localities 1 Council area Mainly The Hills, partly Hornsby Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 2122 · Postcode 2126