Otira Viaduct, Arthurs Pass, New Zealand

Otira Viaduct, Arthurs Pass, New Zealand, originally uploaded by Michael.Sutton.

Arthur's Pass (el. 920 m.) is a mountain pass in the Southern Alps of the South Island of New Zealand. It marks part of the boundary between the West Coast and Canterbury regions, 140 km from Christchurch and 95 km from Greymouth. The pass lies in a saddle between the valleys of the Otira River, a tributary of the Taramakau, in the west and the Bealey River in the east. Arthur's Pass lies on the border of the Selwyn and Westland districts.

A hamlet of the same name (Arthur's Pass) is located about 5 km south of the mountain pass.

History
The pass is named after Sir Arthur Dudley Dobson (1841–1934), who led the first party of Europeans across the pass in 1864. He had been informed of the presence of a pass, which had been used occasionally by Māori hunting parties by a West Coast Māori Chief, Tarapuhi. It is also believed that writer and explorer Samuel Butler had seen the pass several years earlier, but was unable to explore it at that time. The timing was perfect, as the West Coast was soon to be hit by a goldrush, and easy access to the Tasman's coast became imperative.

Road link
State Highway 73 passes over Arthur's Pass and is the highest of only three roads crossing the Southern Alps, the other crossings being the Haast Pass and the Lewis Pass. However, Porter's Pass, on the same road, is higher (at 939 m) than Arthur's Pass, but it is not considered one of the alpine passes, as it is located in the Canterbury foothills not far away from Springfield.

Previously prone to be blocked by landslides or avalanches, the road on the western side of the pass has seen extensive civil engineering work in the late 1990s. Most notably, the impressive Otira Viaduct, near the settlement of Otira and spanning 440 metres of unstable terrain, was completed in 1999.

Rail link
The Midland Line, connecting Christchurch and the West Coast, crosses the Main Divide by means of the Otira Tunnel, between Arthur's Pass township and Otira. When opened in 1923, the tunnel was the longest in the British Empire.