Early on December 12, we crossed the Murray River at Wellington, South Australia. For many years, this was the site of the only river crossing. The ferry is state run and is FREE! The Murray River (River Murray in South Australia) is Australia’s longest river. At 2,375 kilometres (1,476 mi) in length. The Murray River system receives 58% of its natural flow. It is perhaps Australia’s most important irrigated region and is widely known as the food bowl of the nation.