Milford Sound (Piopiotahi) is a glacier-carved fjord in Fiordland National Park, New Zealand, where Mitre Peak rises steeply straight out of the water. Toggle the freshwater lens to see the tannin-stained rainwater layer that floats on the seawater, and the waterfall highlight to see the two permanent cascades down the cliff walls.
Published figures: fjord length about 15 km from the Tasman Sea to the head; Mitre Peak rises about 1,692 m directly from the water; average annual rainfall about 6,400 mm.
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Last reviewed: 2026-07-28 | By: 3D Geographer
Milford Sound - New Zealand's most famous fjord
Milford Sound is a drowned fjord on New Zealand's southwest coast, carved by glaciers during the last Ice Age. The valley was flooded by rising seas, creating one of the world's most dramatic coastal landscapes. Steep cliff walls rise 1,200+ meters directly from water so deep it rivals inland lakes.
The fjord's U-shaped profile is the classic signature of glacial carving. Unlike river valleys, which form narrow V-shaped canyons, glaciers move slowly and widely, sculpting broad, rounded valleys with nearly vertical walls. When such a valley floods, it becomes a fjord.
Milford Sound's high annual rainfall - about 200 days per year - keeps its cliff faces alive with waterfalls. After heavy rain, dozens cascade into the sea. The landscape is ever-changing with the weather: misty in rain, brilliant in rare sunshine, dramatic under racing clouds.
| Length | about 15 km |
| Width | 1-2 km at the entrance, narrower inland |
| Depth | about 291 meters - deep for any fjord |
| Mitre Peak | 1,695 meters (5,560 feet) - the iconic landmark rising near the entrance |
| Annual rainfall | about 200 rainy days - creating the famous waterfalls |
The fjord sits within Fiordland National Park, a UNESCO World Heritage area. It is one of the most visited natural sites in New Zealand, drawing travelers to cruise its waters and hike its valley trails.
Frequently Asked Questions
Where is Milford Sound?
In Fiordland National Park on the South Island of New Zealand.
Is Milford Sound a fjord or a sound?
It is a true fjord - a glacier-carved valley later flooded by the sea - despite being named a "sound".
How tall is Mitre Peak?
About 1,692 m, rising almost directly from the water at the fjord's edge.
Why is the water dark near the surface?
Heavy rainfall creates a tannin-stained freshwater layer that floats on top of the denser seawater, cutting light below.
How much does it rain at Milford Sound?
About 6,400 mm a year on average, among the wettest inhabited places on Earth.
What are the named waterfalls?
Stirling Falls (about 155 m) and Bowen Falls (about 162 m) are the two permanent cascades down the cliff walls.
Is Milford Sound a UNESCO site?
Yes. It is part of Te Wahipounamu - South West New Zealand, a UNESCO World Heritage Area since 1990.
Is this a scientific terrain model?
No. It is an educational explorer using published figures - the wall shape, waterfall placement, and vertical scale are schematic teaching cues, not survey terrain.