It provides an alternative to SH 1 for traffic travelling between Auckland and parts of Northland from Wellsford northwards.

It travels south via The Strand where it reaches the lights at Beach Road and Parnell Rise where it changes to Stanley Street.

The highway travels through the Central Motorway Junction where there are exits to SH 1 both northbound and southbound.

The Northwestern Motorway terminates at a roundabout with Brigham Creek Road and Fred Taylor Drive.

It passes through the communities of Kumeū, Huapai, Waimauku and Helensville, eventually reaching the west coast.