Western Ring Route
Upper Harbour Highway (SH 18) Upper Harbour Motorway (SH 18) Northwestern Motorway (SH 16) Southwestern Motorway (SH 20)
Route information
Length	48 km (30 mi)
History	First section completed in 1955. Route completed in 2017.
Major junctions
North end	SH 1 near Rosedale
Major intersections	SH 16 at Westgate SH 16 at Waterview SH 20A at Mangere SH 20B at Puhinui
South end	SH 20 at Manukau
Location
Country	New Zealand
Major cities	Greenhithe, Hobsonville, Massey, Te Atatu, Waterview, Mount Roskill, Onehunga, Mangere, Auckland Airport, Wiri
Highway system
New Zealand state highways Motorways and expressways List

The Western Ring Route is a motorway system in Auckland, New Zealand. It runs along (from south to north) the entire Southwestern Motorway (State Highway 20), most of the Northwestern Motorway (part of SH 16), the entire Upper Harbour Motorway, and the entire Upper Harbour Highway (the last two forming SH 18).^[1] When the Upper Harbour Highway is upgraded to motorway status, the route will surpass the Southern Motorway to become the longest motorway in New Zealand at 48 kilometres in length. It runs through Manukau, West Auckland, and the North Shore, bypassing the Auckland city centre and thus providing a second motorway route through the Auckland isthmus.^[1]

The ring route had been planned as early as the first half of the 20th century. Some critics have alleged that the rerouting of State Highway 1 over the Auckland Harbour Bridge (to ensure toll revenues) was a primary contributor to the decades-long delays. The rerouting is alleged to have significantly contributed to the need for a massive motorway through the centre of Auckland, severely damaging inner city suburbs such as Freemans Bay and Grafton.^[2]

The section of SH 20 from Queenstown Road to Richardson Road (the Mount Roskill Extension) opened on 15 May 2009.^[3] The section of SH 18 connecting the Greenhithe Bridge and SH 16 (the Upper Harbour Motorway) and the extension of SH 16 to Brigham Creek Road opened in August 2011.^[4]

Construction of the Waterview Connection began in late 2011 and it was opened to traffic on 2 July 2017. This completed the route as a highway, with a remaining section of SH 18 still to be upgraded to motorway standard. The opening of the Waterview Connection allows traffic to travel along the entire length of the highway, from SH 1 near Rosedale to SH 1 at Manukau.

The Upper Harbour Highway section was upgraded to motorway status as part of the Northern Corridor Improvements project. Construction started in April 2018 and was completed in June 2023.^[5]

Location	km	#	Destinations	Notes
	0.0		SH 1 Northern Motorway (south) – Auckland	Western Ring Route begins
			SH 1 Northern Motorway (north) – Whangarei
			Caribbean Drive
			Paul Matthews Drive
			Unsworth Drive	Southbound exit only
	2.4	2	Route 26 Albany Highway	Motorway begins
Greenhithe	4.3	4	Greenhithe Road	Southbound exit and northbound entrance
	6.2	6	Tauhinu Road	Northbound exit and southbound entrance
	7.4	Upper Harbour Bridge over Waitematā Harbour
Hobsonville		8	Squadron Drive	Southbound exit and northbound entrance
		9	Brigham Creek Road – Whenuapai, Helensville	to north
		10	Trig Road	Southbound exit and northbound entrance
Westgate		11	Route 32 Hobsonville Road	Southbound exit and northbound entrance
			SH 16 Northwest Motorway (north) – Kumeu, Helensville
	19.4		Route 32 Hobsonville Road	Northbound exit and southbound entrance
Massey East	17.8	18	Royal Road	Northbound exit and southbound entrance
Lincoln North	15.6	16	Route 19 Lincoln Road – Henderson
Te Atatū South	13.5	14	Route 13 Te Atatu Road – Henderson
Avondale North	12.3	12	Patiki Road – Avondale, New Lynn	Southbound exit and northbound entrance
	10.8	11	Rosebank Road	Westbound exit and eastbound entrance
Point Chevalier	8.2	8B	SH 20 Southwest Motorway (south)	Beginning of Waterview Connection
	8.1	8A	Route 11 Great North Road – Avondale, New Lynn	Southbound exit and northbound entrance
			SH 16 Northwest Motorway (east) – Auckland City Centre, Port
		Waterview Tunnel
Mount Roskill
			Maioro Street
		18	Route 4 Dominion Road
Hillsborough		16	Route 15 Hillsborough Road
		15	Route 12 Queenstown Road — Auckland City Centre	Northbound exit and southbound entrance
Onehunga		13	Neilson Street — Onehunga Wharf, Onehunga, Penrose, Mt Wellington
		Māngere Bridge over Manukau Harbour
Māngere Bridge
		12	Mahunga Drive — Māngere Bridge Township, Favona	Southbound exit and northbound entrance
Māngere		10	Walmsley Road	Southbound
			Coronation Road	Northbound
		9	SH 20A — Airport	No southbound entrance (use SH20B or Massey Road) Carriageway mainline connects north to west, traffic proceeding from/to south on motorway must 'exit'.
		7	Route 14 Massey Road
Puhinui		3	SH 20B Puhinui Road — Airport	No northbound exit (use Cavendish Drive) Southbound entrance and connection to SH 20B and
		3	Route 30 Cavendish Drive	No southbound exit (use Puhinui Road) Northbound entrance and connection to SH 20B and
Manukau CBD		2	Lambie Drive — Manukau City Centre
		1	SH 1 Southern Motorway north — Auckland	Western Ring Route ends
			SH 1 Southern Motorway south — Hamilton
1.000 mi = 1.609 km; 1.000 km = 0.621 mi