 The national park protects the landforms of Bradleys Head, Clark Island, Dobroyd Head, Fort Denison, Georges Head, Goat Island, Middle Head, Nielsen Park, Rodd Island, Shark Island, Sydney Heads including the Quarantine Station at North Head and The Gap bluff at South Head.The national park also protects the waterway between North Head and Dobroyd Head, defined as the North Sydney Harbour Aquatic Reserve.Parts of the national park lie outside the harbour and face the Tasman Sea.