Tonkin Highway

Tonkin Highway is a 45-kilometre (28 mi) north-south highway and partial freeway in Perth, Western Australia, linking Perth Airport and the Kewdale with the city's north-eastern and south-eastern suburbs. The northern terminus is at Reid Highway in Malaga and the southern terminus is at Thomas Road in Oakford. It forms the entire length of State Route 4, and connects to several major roads, including Great Eastern Highway, Leach Highway, Roe Highway, and Albany Highway.

Planning for the route began in the 1950s, with the first segment between Wattle Grove and Cloverdale opened in 1980. Over the next five years, that section was extended north to Great Eastern Highway and south to Albany Highway, and a discontinuous section was constructed north of the Swan River. In 1988 the Redcliffe Bridge linked these sections. The next major works on the highway, between 2003 and 2005, extended the highway south to Thomas Road.

The Gateway WA project, which began in 2013, will see the central section of the highway upgraded to a six-lane freeway-standard road by 2017. Further extensions to both the northern and southern extents of the highway are planned, which would connect the highway to the proposed Perth Darwin National Highway in Malaga, and to South Western Highway near Jarrahdale Road.