The Gray River is a river in the Fiordland

Fiordland

Fiordland is a geographic region of New Zealand that is situated on 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 ocean-flooded, steep western valleys...

 area of New Zealand

New Zealand

New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

. It arises in the Cameron Mountains in Fiordland National Park

Fiordland National Park

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...

 and flows south-west and then north-west into Revolver Bay, on the south side of Preservation Inlet

Preservation Inlet

Preservation Inlet is the southernmost fjord in Fiordland National Park and lies on the southwest corner of the South Island of New Zealand.-Geography:...

.

The river may have once flowed into Kisbee Bay, south of its current mouth, but it built a broad flat by depositing glacial debris, changing its course to Revolver Bay.