Fiordland is a geographic region of New Zealand in the south-western corner of the South Island, comprising the western-most third of Southland. Most of Fiordland is dominated by the steep sides of the snow-capped Southern Alps, deep lakes, and its steep, ocean-flooded western valleys. The name "Fiordland" comes from a variant spelling of the Scandinavian word for this type of steep valley, "fjord".
Fiordland features a number of fiords (often named sounds), of which Milford Sound is the most famous, though Doubtful Sound is larger and has more, and longer, branches (but is less accessible). Situated within Fiordland are Browne Falls and Sutherland Falls, which rank among the tallest waterfalls in the world, and New Zealand's three deepest lakes, Lake Hauroko, Lake Manapouri, and Lake Te Anau. Several other large lakes lie nearby, and Fiordland and the surrounding parts of Southland and Otago Regions are often referred to as the Southern Lakes. This part of New Zealand, especially to the west of the mountain divide of the Southern Alps, has a very wet climate with annual average of 200 rainy days and annual rainfall varying from 1200mm in Te Anau to 8000mm in Milford Sound.
Fiordland has never had any significant permanent population. Even the Maori only visited temporarily for hunting, fishing and to collect the precious stone pounamu (New Zealand jade) from Anita Bay and the mouth of Milford Sound.
The area was administered as Fiord County from 1876 until it was absorbed into neighbouring Wallace County in 1981. Since 1989 it has been part of Southland District, and the wider Southland Region.