Tonkin Highway

Tonkin Highway Western Australia
General information
Type	Highway
Length	81 km (50 mi)[1]
Opened	1980
Maintained by	Main Roads Western Australia
Route number(s)	State Route 4
Major junctions
North end	Great Northern Highway (National Highway 94 / National Route 1)/ Brand Highway (National Route 1), Muchea
	Gnangara Road, (State Route 84) Reid Highway (State Route 3) Great Eastern Highway (National Highway 94 / National Route 1) Leach Highway (State Route 7) Roe Highway (State Route 3) Albany Highway (State Route 30)
South end	Thomas Road (State Route 21), Oakford
Location(s)
Major suburbs	Bullsbrook, Ellenbrook, Bayswater, Perth Airport, Forrestfield, Maddington, Gosnells, Champion Lakes
Highway system
Highways in Australia National Highway • Freeways in Australia Highways in Western Australia
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Tonkin Highway is an 81-kilometre-long (50 mi) north–south highway and partial freeway in Perth, Western Australia, linking Perth Airport and Kewdale with the city's north-eastern and south-eastern suburbs. As of April 2020, the northern terminus is at the interchange with Brand Highway and Great Northern Highway in Muchea, 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. Besides Brand Highway and Great Northern Highway, it also connects to Reid Highway, Great Eastern Highway, Leach Highway, Roe Highway, and Albany Highway.

Planning for the route began in the 1950s, but the first segment between Wattle Grove and Cloverdale was not opened until 1980. Over the next five years, the highway 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, and three years later, Reid Highway became the northern terminus. The next major works on the highway, between 2003 and 2005, extended the highway south to Thomas Road.

The central section of Tonkin Highway was upgraded to a six-lane freeway-standard road between 2013 and 2015, as part of the Gateway WA project to improve the wider road network around Perth Airport. From 2016 to 2020, construction commenced to upgrade the section of Tonkin Highway between Guildford Road and the original Reid Highway terminus to a six-lane freeway-standard road, and to build a four-lane freeway standard road up to Muchea, as part of the NorthLink WA project. The extension was originally known as the Perth Darwin National Highway. Planning provisions have been made for Tonkin Highway to be extended south of Byford in the future.