Australia's longest dual-carriageway highway evolved from an impenetrable brush into a modern transit artery.

Countries & Cities · Published 15 October 2026 Swipe more like this →

In short: Spanning 840 kilometres between Melbourne and Sydney, the Hume Highway is a vital national link. While today it is a high-speed motorway, its path was once blocked by the dense Bargo brush, forcing early explorers to rely on Aboriginal knowledge to navigate the rugged terrain of the Great Dividing Range.

The route's history is deeply tied to the expansion of the Australian colonies. In 1818, explorer Charles Throsby successfully navigated the Bargo brush to reach the Southern Tablelands, paving the way for rapid agricultural development. By 1824, Hamilton Hume and William Hovell completed an overland journey that cemented the path as a primary corridor. Governor Lachlan Macquarie ordered the construction of the Great Southern Road in 1819, though it remained little more than a primitive track for decades. By 1858, the southern reaches were still described as a scarcely formed bullock track, requiring significant improvements in the 1860s to bridge creeks and metal the road surface.

The modern highway is a feat of engineering that overcomes the steep escarpment of the Great Dividing Range. To climb from the coast to the tablelands, the route utilizes the Bargo Ramp, a geological feature that provides one of the few accessible crossings. Between the Nepean River and Aylmerton, the road climbs over 430 metres across 25 kilometres. Engineers avoided the Razorback Range by utilizing four high-level bridges to traverse the gorge systems of the Wollondilly and Shoalhaven rivers, minimizing the need for massive earthworks while maintaining a sustained incline that is often imperceptible to modern drivers traveling at 110 km/h.

The transition to a continuous dual-carriageway was a decades-long project that concluded on 7 August 2013 with the opening of the Holbrook bypass. This massive infrastructure effort involved numerous stages, including the 1973–1992 construction of the Casula to Berrima section and the 2005 completion of the Craigieburn Bypass. Today, the route is managed under the M31 designation, serving as a critical artery for freight and travel. While the road has been modernized, remnants of its past remain, such as the stone arch culvert built by Surveyor-General Thomas Mitchell at Towrang Creek in 1833, which stands as a testament to the early efforts to tame this challenging landscape.

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