Thornleigh is a suburb in the Northern Sydney region, or Upper North Shore of Sydney in the state of New South Wales, Australia. Thornleigh is located 22 kilometres north-west of the Sydney central business district in the local government area of Hornsby Shire. The source of the Lane Cove River is located in Thornleigh. Geography Thornleigh is bounded to the north by Waitara Creek and south by the Lane Cove National Park. Thornleigh borders the suburbs of Normanhurst, Hornsby, Wahroonga, Westleigh and Pennant Hills. Thornleigh offers great district views, and the topography varies greatly with many established areas built around bushland settings and into the hills to afford the great views. The northern areas of the suburb bounded by Larool Creek and Waitara Creek are leafy and lush with vegetation and native fauna including rainbow lorikeets, kookaburras, cockatoos, and bush turkeys. Majorie Headen Lookout is a vantage point which overlooks Larool and Waitara Creek Valley. The area bounded near the train station and the Comenarra Parkway include early examples of Federation and Californian Bungalow style properties. History Thornleigh was originally part of the land that the Kuringai people settled. The first non-indigenous people to explore the area of Thornleigh were a party led by Governor Arthur Phillip in 1788. Settlers moved into the area in the 1830s and among them were James Milson, Patrick Duffy, John Thorn and Samuel Horne. Thornleigh is named after Constable John Thorn, who, along with Constable Horne, captured bushrangers Dalton and John MacNamara, leader of the North Rocks gang, on 22 June 1830, and were granted land as a reward in 1838. Horne's land became Hornsby (now Normanhurst), and Thorn's land became Thornleigh. Orcharding was one of the major mainstays of Thornleigh during the late nineteenth century. Land sales posters used this as an attraction for prospective settlers describing the area as "beautifully situated (and) surrounded by magnificent orchards, the fruit from which affords a splendid proof of the fertility of the soil and mildness of the climate". Among the orchard growers was Patrick Michael Duffy, after which Duffy Avenue was named. After Patrick Duffy's passing, his land was subdivided and passed down to his son Patrick Duffy Jnr. Eventually part of this land was purchased by the wealthy Friend family who built the Windyhaugh property on Duffy Avenue, which was later used as the first Presbyterian Fellowship Union camp in the Commonwealth. As part