The Northwestern Motorway (also known historically as the Auckland–Kumeu Motorway), part of State Highway 16 (SH16), is the major western route and secondary northern route out of Auckland in New Zealand. Twenty-one kilometres in length, the motorway runs from Stanley St in Parnell through the Central Motorway Junction, and west through urban Auckland and Waitakere before continuing northwest and terminating outside of Kumeu. Its western terminus is at Brigham Creek Road in Whenuapai. A large part of it forms the middle section of the Western Ring Route.