Which New Zealand highway runs the length of both main islands?

New Zealand’s State Highway 1 runs the length of both main islands.

SH 1 is the longest and most significant route in New Zealand’s state-highway network. Its North Island section runs from Cape Reinga to Wellington, while its South Island section continues from Picton to Bluff. The two sections are separated by Cook Strait, so the highway is not one uninterrupted piece of pavement: travelers use an interisland ferry to make the crossing.

The route passes through or near major centers including Auckland, Hamilton, Wellington, Christchurch, Dunedin, and Invercargill. It is designated SH 1N in the North Island and SH 1S in the South Island, but both sections carry the same national route number.

State Highway 6 is extensive and follows much of the South Island’s western side, while State Highway 2 and State Highway 8 serve important regional corridors. Neither spans both main islands. SH 1 has also been shortened and rerouted over time as expressways and bypasses were built.