Great Dividing Range

Lore & Background

The range has experienced significant erosion since. Evidence remains in some places of their traditional way of life including decorated caves, campsites and trails used to travel between the coastal and inland regions. Crossing the Blue Mountains was particularly challenging due to the mistaken idea that creeks should be followed rather than ridges, and the almost impenetrable sandstone mountains. A road was built to Bathurst by convicts within six months.

Reader's Guide

The Great Dividing Range is significant as mainland Australia's most substantial topographic feature and the definitive watershed for eastern river systems. It shields much of the southeast from south-westerly cold fronts in the cool season. The range was an obstacle to early European exploration, but Aboriginal walking trails helped settlers find routes across it. Today, many areas remain remote, with only one major road crossing the highlands from north to south in eastern Victoria.

Did You Know?

• The Great Dividing Range is the fifth-longest land-based mountain chain in the world and the longest entirely within a single country.
• The range was formed during the Carboniferous period—over 300 million years ago—when Australia collided with what are now parts of South America and New Zealand.
• A usable ridge-top route across the Blue Mountains was discovered by an expedition jointly led by Gregory Blaxland, William Lawson and William Charles Wentworth.
• The range contains three World Heritage Areas: the Greater Blue Mountains Area, Gondwana Rainforests, and Wet Tropics of Queensland.
• Rivers east of the range drain into the South Pacific, Tasman Sea, or Bass Strait; rivers west drain into the Murray–Darling basin, Lake Eyre basin, or the Gulf of Carpentaria.

Vast Geography and Structural Diversity

Far from a single continuous wall, the range functions as a sprawling network of dozens of distinct subranges, separated by elevated basins and broad rolling tablelands. Its width shifts dramatically, from about 110 to 480 kilometers depending on where you measure.

Geological Origins and Tectonic Sculpting

The Rocky Mountains took shape between 55 and 80 million years ago during an event geologists call the Laramide orogeny. During this period, several tectonic plates began sliding beneath the North American plate. The subduction angle was notably shallow, which produced a broad belt of uplifted terrain running down the western side of the continent rather than a narrow volcanic arc. Over the millions of years since the initial uplift, additional tectonic activity continued to reshape the landscape, while glaciers carved and sculpted the range into the dramatic peaks and deep valleys visible today. The interplay of slow plate movement, repeated uplift, and glacial erosion over tens of millions of years created the complex topography that defines the range. The result is a geologically ancient yet still evolving mountain system whose structure reflects the layered history of continental collision and ice-age modification.

Indigenous Roots and European Encounter

Long before any European set foot in the region, however, humans had already begun inhabiting the mountains at the close of the last ice age. The arrival of these outsiders set in motion the initial economic exploitation of the mountains, driven primarily by the pursuit of minerals and fur. Despite this resource-driven interest, the range itself never supported a dense human population, remaining largely sparsely settled throughout its history.

Modern Conservation, Tourism, and Population Shifts

Today, public parks and forest lands shield a substantial portion of the Rocky Mountains from development, and the range draws visitors from around the world for hiking, camping, mountaineering, fishing, hunting, mountain biking, snowmobiling, skiing, and snowboarding. Colorado, home to most of the range's highest summits and an average elevation of about 2,100 meters, is a particular magnet for outdoor recreation. Despite this popularity, the Rockies remain sparsely populated, averaging only four people per square kilometer, with very few cities exceeding 50,000 residents. Yet the demographic picture has shifted markedly in recent decades. Between 1950 and 1990, statewide populations in the Rocky Mountain states surged, growing 35 percent in Montana and roughly 150 percent in Utah and Colorado. Mountain towns have seen even steeper climbs: several communities doubled their populations between 1972 and 2012, and Jackson, Wyoming, grew by 260 percent over the same span, expanding from 1,244 to 4,472 residents.