Brookton Highway is a 112 kilometre long undivided single carriageway highway in Western Australia, running from the southern Perth suburb of Kelmscott, through Westdale, to the southern Wheatbelt town of Brookton. It is signposted as State Route 40, however the route and highway continues on far past Brookton, passing through Corrigin, Kondinin, Hyden, Lake King, and finishing at South Coast Highway, just west of Ravensthorpe.