Port MacDonnell, originally known as Ngaranga, is the southernmost town in South Australia. The small port is located in the Limestone Coast r…Port MacDonnell, originally known as Ngaranga, is the southernmost town in South Australia. The small port is located in the Limestone Coast region, about 477 kilometres south-east of Adelaide and 28 kilometres south of Mount Gambier, in the District Council of Grant local government area. Once a busy shipping port, the town now relies heavily on its fishing and summer tourism industries, particularly the rock lobster industry, proclaiming itself "Australia's Southern Rock Lobster Capital".