De Witt Island, also known as Big Witch, is a 517 hectares (1,280 acres) island in south-eastern Australia. It is the largest of the Maatsuyker Island Group, lying close to the southern end of the south-western coast of Tasmania. Its highest point is 354 metres (1,161 ft) above mean sea level. It is part of the Southwest National Park, and thus within the Tasmanian Wilderness World Heritage Site. Although currently uninhabited, it has a long history of human usage, including logging and occasional habitation.