Fiordland National Park occupies the southwest corner of the South Island of New Zealand. It is the largest of the 14 national parks in New Zealand, with an area of 12,500 km2, and a major part of the Te Wahipounamu World Heritage site. The park is administered by the Department of Conservation.

During the cooler past, glaciers carved many deep fiords, the most famous (and most visited) of which is Milford Sound. Other notable fiords include Doubtful Sound and Dusky Sound. From one of the peaks within Fiordland National Park, a view of Mount Aspiring/Tititea to the far north can be observed.

Fiordland’s coast is steep and crenellated, with the fiords running from the valleys of the southern ranges of the Southern Alps, such as the Kepler and Murchison Mountains. At the northern end of the park, several peaks rise to over 2,000 metres.

Ice has carved islands from the mainland, leaving two large uninhabited offshore islands, Secretary Island and Resolution Island. Several large lakes lie wholly or partly within the park’s boundaries, notably Lake Te Anau, Lake Manapouri, Lake Monowai, Lake Hauroko, and Lake Poteriteri. The Sutherland Falls, to the southwest of Milford Sound on the Milford Track, are among the world’s highest waterfalls.

Prevailing westerly winds blow moist air from the Tasman Sea onto the mountains; the cooling of this air as it rises produces a prodigious amount of rainfall, exceeding seven metres in many parts of the park. This supports the lush temperate rain forests of the Fiordland temperate forests ecoregion.