It runs close to the west coast of the Northland Region of New Zealand.

It then turns roughly westwards, reaching the Hokianga harbour at its Omanaia River arm.

It continues west, reaching Opononi and Ōmāpere at the mouth of the harbour, before turning southeast to parallel the coast.

At Dargaville, the highway meets SH 14, and continues southeastwards along the edge of the Wairoa River to Ruawai before turning eastwards.

It briefly skirts the edge of the Arapaoa River arm of the Kaipara Harbour before passing through Paparoa and Maungaturoto and ending at its junction with SH 1 at Brynderwyn, 15 km (9.3 mi) south of Waipu.