Croker Island is an island in the Arafura Sea off the coast of the Northern Territory, Australia, 250 km northeast of Darwin. It was the site of the Croker Island Mission between 1940 and 1968. At the earliest time of European contact, the Indigenous people of Croker Island were the Jaako, an Aboriginal Australian people who spoke Marrgu, a language isolat…Croker Island is an island in the Arafura Sea off the coast of the Northern Territory, Australia, 250 km northeast of Darwin. It was the site of the Croker Island Mission between 1940 and 1968. At the earliest time of European contact, the Indigenous people of Croker Island were the Jaako, an Aboriginal Australian people who spoke Marrgu, a language isolate. The modern Indigenous communities speak Iwaidja and Maung, Kunwinjku and English.