Home Postcodes by state VIC 3450 Postcode 3450 3450 is the postcode for 2 localities in VIC: Castlemaine and Moonlight Flat. Localities with postcode 3450CastlemaineVICMoonlight FlatVIC Postcode 3450 State or territory Victoria (VIC) Localities 2 Council area Mount Alexander Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 3448 · Postcode 3451