Is a range of mountains, plateau and escarpments extending off the Great Dividing Range about 4.8km north west of Wolgan Gap ina generally south east direction for about 96km and terminating at Emu Plains.For about two thirds of its length it is traversed by the Great Western Highway and the Main Western Railway. Several established towns are situated on its heights, including Katoomba, Blackheath, Mount Victoria, and Springwood. It forms the watershed between Coxs River to the south and the Grose and Wolgan Rivers to the north. The range is bounded on the north by the Wolgan and Colo Rivers, on the west and south by Coxs River and Lake Burragorang, and on the east by the Nepean-Hawkesbury River. Blue Mountains Range is shown on the Map of Colony of NSW by Robert Dixon, 20th July 1837. The range was crossed by Blaxland, Wentworth and Lawson in 1813. Surveyor George Evans was instructed by Governor Macquarie to survey the road over the Blue Mountains, which he started in November 1813. William Cox was then commissioned to build the road. Work started on 18th July 1814 and was completed in March 1815.