Which mountain range is Australia's longest, extending along much of its eastern side?

The Great Dividing Range is Australia's longest mountain range, extending along much of the continent's eastern side.

The range runs for about 3,500 kilometres from northeastern Queensland through New South Wales and Victoria. It is not a single unbroken wall of mountains; instead, it includes many plateaus, escarpments and separate ranges.

Its watershed is especially important. Rivers on the inland side generally flow toward the Murray–Darling Basin, while rivers on the eastern side reach the Pacific Ocean. This elevation difference has strongly influenced Australian farming, cities and transport routes.

The Australian Alps form the range's southeastern highland section. Mount Kosciuszko, at 2,228 metres, is the highest peak in Australia, although some offshore Australian territories have higher summits. The Great Dividing Range is therefore broader than the Australian Alps alone.