The South Island forms one of the two major islands of New Zealand, the other being the North Island. The Maori name for the South Island is Te Wai Pounamu which means “The Greenstone Water” (greenstone being jade). In the 19th century, some maps named the South Island as Middle Island (or New Ulster), and the name South Island (or New Leinster) was attributed to today’s Stewart Island/Rakiura.

It has an area of 151,215 square km (58,093 square miles), making it the world’s 12th-largest island. Along its west coast runs the mountain chain of the Southern Alps; Aoraki/Mount Cook is the highest point, 3,754 m (12,283.3′) above sea level.

The South Island is often called the Mainland (somewhat humorously) because it is larger than the North Island, and because it existed first according to the corresponding Maori legend. The North island, however, is more populous, being home to three million out of a total of four million kiwis.

Some North Islanders (especially Aucklanders) even refer to the South Island as though it were a single town, stating for example that some event occurred “down south” without being more specific about a particular town or city.