Goat Island is an island in Sydney Harbour, in New South Wales, Australia. The island is approximately 300m wide in a north/south direction and 180m long in an east/west direction. It covers an area of 5.4 hectares (13 acres) The island is located north-west of the Sydney central business district. Goat Island lies off the shores of the Sydney suburbs of Balmain and Millers Point, at the junction of Darling Harbour with the main channel of Sydney Harbour. Over the years Goat Island has served as a quarry, convict stockade, explosives store, police station, fire station, boatyard and film set. Today the island forms part of the Sydney Harbour National Park.