Van Diemen Gulf (11°49′S131°57′E) is a gulf between Arnhem Land, of the attached Cobourg Peninsula and Melville Island in northern Australia. It is connected to the Timor Sea in the west by the Clarence Strait (near the city of Darwin), and to the Arafura Sea in the north by Dundas Strait (between Melville Island and Cobourg Peninsula). It is bounded to the southeast by the Kakadu National Park.