Great Dividing Range

The Great Dividing Range, also called the East Australian Cordillera or Eastern Highlands, is a vast system of mountain ranges, plateaus, and rolling hills that runs along eastern Australia. It stretches more than 3,500 kilometers from Dauan Island in the Torres Strait off the northern tip of Cape York Peninsula, down the entire eastern coast through Queensland and New South Wales, then turns west across Victoria and gradually fades into the Wimmera plains as low hills west of the Grampians region. Its width ranges from about 160 kilometers to over 300 kilometers. This is the fifth-longest mountain chain on land in the world and the longest that lies entirely within one country. It is the most significant topographic feature of mainland Australia and acts as the main watershed for eastern Australia’s river systems, which is how it got its name.

The range is not a single continuous chain but a complex of mountain ranges, plateaus, hilly uplands, and escarpments with an ancient geological history. The physiographic division is called the East Australian Cordillera. In some areas the terrain is flat or has very low hills, while typical highlands range from 300 to 1,600 meters in height. The rocks—limestones, sandstone, quartzite, schists, and dolomite—were shaped by faulting and folding. The crest of the range is defined by the watershed boundary: rivers east of it drain into the South Pacific, Tasman Sea, or Bass Strait, while rivers west of it drain in various westerly directions. These include the Murray–Darling basin flowing southwest into the Great Australian Bight, the Lake Eyre basin flowing southwest into Kati Thanda–Lake Eyre, and the rivers of western Cape York Peninsula flowing west or northwest into the Gulf of Carpentaria. The higher and more rugged parts are not always on the crest; they can be branches or offshoots. The term "Great Dividing Range" may refer only to the watershed crest or to the entire upland complex, which at some points is up to 400 kilometers wide. Notable ranges and features within it have their own names. The highest point in Australia, Mount Kosciuszko at 2,228 meters, is in the Snowy Mountains portion of the southern range. The Greater Blue Mountains Area, Gondwana Rainforests, and Wet Tropics of Queensland are World Heritage Areas located in the range.

The sharp rise between the coastal lowlands and the eastern uplands affects Australia’s climate, mainly through orographic precipitation, and the areas of highest relief have impressive gorges. East of the range in southern New South Wales, a Föhn effect occurs: a dry wind from the range that raises air temperature and reduces moisture on the lee side, increasing fire danger in warm months. This happens because damp low-level air is partially blocked by the mountains, and drier upper-level air subsides on the leeward side, heating up through adiabatic compression and creating a rain shadow. In the cool season, the range shields much of the southeast—including Sydney, the Central Coast, Hunter Valley, Illawarra, the ACT, the Monaro, and the South Coast—from south-westerly cold fronts from the Southern Ocean. These fronts bring chilling rain, sleet, and snow to the upwind side, such as the western Central Tablelands, South West Slopes, and Snowy Mountains, which have wetter winters. Upwind locations include Crookwell, Batlow, Tumut, Corryong, Bright, Beechworth, Eildon, Tolmie, and parts of West Gippsland. On the downwind eastern slopes, places like Cooma, Omeo, Goulburn, Bowral, Bombala, Nimmitabel, and Canberra are warmer and drier for their altitude. Towns on the crest, such as Oberon, Shooters Hill, and Sunny Corner, are exposed from all directions and have evenly spread rainfall. The main ski resorts in New South Wales—Thredbo Village, Perisher, and Charlotte Pass—lie between the leeward and windward sides, with Thredbo more leeward and Charlotte Pass more windward. They get substantial precipitation from over the crest but lack the persistent cloud cover of truly windward locations on the western face, such as Cabramurra, Kiandra, Mount Buller, Falls Creek, Mount Hotham, Mount Buffalo, and Mount Baw Baw.