State Highway 6 (SH 6) is a major New Zealand state highway. It extends from the Marlborough region in the northeastern corner of the South Island across the top of the island, then down the length of the island, initially along the West Coast and then across the Southern Alps through inland Otago and finally across the Southland Plains to the island's south coast. Distances are measured from north to south.
The highway is the longest single highway in the country, though it is shorter than the combined totals of the two highways that comprise SHÂ 1, SHs 1N and 1S.