Prospect Highway is an 11.1-kilometre (6.9 mi)[1] secondary urban road linking Baulkham Hills and Pemulwuy in the western suburbs of Sydney, New South Wales, Australia.

Blacktown Road splits off southeast after a short distance: the name changes again back to Prospect Highway and continues south through Prospect until it crosses over both Great Western Highway and M4 Western Motorway, continuing south until it eventually terminates at the intersection with the Liverpool–Parramatta Transitway in Pemulwuy; the road continues southwards as Widemere Road.

[6] Later, the section of Seven Hills Road, between the intersection with Station Road and Johnson Avenue, and the intersection with Wall Park Avenue in Seven Hills, was also officially renamed Prospect Highway on 27 November 1992.

Under this act, Prospect Highway retains its declaration as Main Road 644.

In 2015, the NSW Government Roads & Maritime Services commenced planning an upgrade of a 3.6-kilometre (2.2 mi) section of the highway between Reservoir Road in Prospect to St Martins Crescent in Blacktown.