What is the Blue Mountains?

The Blue Mountains are a sandstone plateau range west of Sydney, rising to about 1,189 metres at Mount Bindo and stretching across about 11,400 square kilometres. They form part of the Great Dividing Range and are most famous for the dramatic eucalyptus forest valleys and cliffs that define their national park.

The mountains are named for the blue haze that hangs over them, caused by volatile oils released by the dense eucalyptus forest scattering sunlight. Spectacular natural features include the Three Sisters at Echo Point in Katoomba, Wentworth Falls, the Grose Valley, the Jamison Valley, and the Glow Worm Tunnel. The Greater Blue Mountains Area was inscribed on the UNESCO World Heritage List in 2000 in recognition of the unique evolution and diversity of Australian eucalyptus species, with 96 species growing in the mountains, about 13 per cent of all eucalyptus species worldwide.

For the first 25 years of British settlement, the Blue Mountains seemed impassable and confined the colony to the coastal plain. In 1813 Gregory Blaxland, William Lawson, and William Wentworth crossed the mountains via the ridge route now followed by the Great Western Highway, opening the western plains to pastoralism. The Bathurst gold rushes from 1851 followed, transforming colonial New South Wales. The route is followed today by the Main Western railway line, the world's first mountain railway built in the 1860s.

The Blue Mountains were the worst-affected area of the 2019 to 2020 Black Summer bushfires, with about 80 per cent of the World Heritage Area burnt. The Wollemi pine, an ancient conifer rediscovered in 1994 in a hidden Blue Mountains canyon and previously known only from fossils, was protected by emergency firefighting that became an internationally watched conservation operation.