Forrest Highway is a 95-kilometre-long (59 mi) highway in Western Australia's Peel and South West regions, extending Perth's Kwinana Freeway from east of Mandurah down to Bunbury. Old Coast Road was the original Mandurah–Bunbury route, dating back to the 1840s. Part of that road, and the Australind Bypass around Australind and Eaton, were subsumed by Forrest Highway. The highway begins at Kwinana Freeway's southern terminus in Ravenswood, continues around the Peel Inlet to Lake Clifton, and heads south to finish at Bunbury's Eelup Roundabout. There are a number of at-grade intersections with minor roads in the shires of Murray, Waroona, and Harvey including Greenlands Road and Old Bunbury Road, both of which connect to South Western Highway near Pinjarra.

The Kwinana Freeway is a 72-kilometre (45 mi) freeway in and beyond the southern suburbs of Perth, Western Australia, linking central Perth with Mandurah to the south. It is the central section of State Route 2, which continues north as Mitchell Freeway to Clarkson, and south as Forrest Highway towards Bunbury. A 4-kilometre (2.5 mi) section between Canning and Leach highways is also part of National Route 1. Along its route are interchanges with several major roads, including Roe Highway and Mandjoogoordap Drive. The northern terminus of the Kwinana Freeway is at the Narrows Bridge, which crosses the Swan River, and the southern terminus is at Pinjarra Road, east of Mandurah.