The Murray River or River Murray is Australia's longest river at 2,508 kilometres (1,558 mi) in length, the Murray rises in the Australian Alps, draining the western side of Australia's highest mountains and, for most of its length, meanders across Australia's inland plains, forming the border between the states of New South Wales and Victoria as it flows to the northwest, before turning south for its final 500 kilometres (310 mi) into South Australia, reaching the ocean at Lake Alexandrina.