The Wolgan River rises on the Newnes Plateau north of Lithgow then falls into a wide, cliffbound basin of farmland. Downstream, the valley narrows towards the old oil-shale industry ‘ghost town’ of Newnes where it turns to the east and enters Wollemi National Park.
Flowing through the rugged Wollemi Wilderness the river becomes a major tributary of the Colo River, which runs out into the settled lands of the Hawkesbury after more than 100 kilometres of wild sandstone gorge – perhaps the greatest gorge system in Australia and a centrepiece of the largest wilderness in New South Wales.
The Wolgan is one of three great cliff-walled valleys in the Greater Blue Mountains. The others are the Capertee, just to north of the Wolgan, and the most well-known, the Grose Valley. These spectacular chasms owe their shape to the softer layers of shale on the lower slopes, which wear back and undercut the resistant sandstones above. Great blocks topple down, leaving ochre-coloured cliffs standing up to 300 metres high.
The remote forests of the Wolgan are a stronghold for threatened animals which can now only survive in places such as this. Koalas, Brush-tailed Rock Wallabies, Yellow-bellied Gliders, Turquoise Parrots, Glossy Black-cockatoos and Powerful Owls all thrive in this protected sanctuary.