The Cook River / Weheka is in the South Island

South Island

The South Island is the larger of the two major islands of New Zealand, the other being the more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman Sea, to the south and east by the Pacific Ocean...

 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...

. The headwaters are from the La Perouse Glacier on the western flanks of the Southern Alps

Southern Alps

The Southern Alps is a mountain range extending along much of the length of New Zealand's South Island, reaching its greatest elevations near the island's western side...

, and it flows west, then northeast, then northwest and into the Tasman Sea

Tasman Sea

The Tasman Sea is the large body of water between Australia and New Zealand, approximately across. It extends 2,800 km from north to south. It is a south-western segment of the South Pacific Ocean. The sea was named after the Dutch explorer Abel Janszoon Tasman, the first recorded European...

. Its tributaries include the Balfour River

Balfour River

The Balfour River is a river in the Westland district of New Zealand. Its source is the Balfour Glacier and it runs west then northwest for about 5 km to the Cook River/Weheka-References:* - Search for Place Names...

, fed by the Balfour Glacier, and the Fox River

Fox River, Westland

The Fox River is a river in the Westland District of New Zealand. It arises in two places; from a spring in the Fox Range, and from the head of the Fox Glacier. It runs west into the Cook River/Weheka, shortly before it exits into the Tasman Sea....

, fed by the Fox Glacier

Fox Glacier

The Fox Glacier is a long glacier located in Westland Tai Poutini National Park on the West Coast of New Zealand's South Island...

. Much of the river lies within the Westland Tai Poutini National Park.
The river was renamed from Cook River to Cook River / Weheka as a result of the Ngai Tahu Claims Settlement Act 1998.

Brown trout

Brown trout

The brown trout and the sea trout are fish of the same species....

 can be fished for in the river.

Access along the river by foot is difficult beyond the junction with the Balfour River. There are no approved helicopter landing sites in the river valley, but there are chamois

Chamois

The chamois, Rupicapra rupicapra, is a goat-antelope species native to mountains in Europe, including the Carpathian Mountains of Romania, the European Alps, the Tatra Mountains, the Balkans, parts of Turkey, and the Caucasus. The chamois has also been introduced to the South Island of New Zealand...

, tahr

Tahr

Tahrs are three species of large Asian ungulates related to the wild goat. Until recently the three species were believed to be closely related and were placed in a single genus, Hemitragus. Genetic studies have proved that the three tahrs are not as closely related as thought earlier...

 and small numbers of red deer

Red Deer

The red deer is one of the largest deer species. Depending on taxonomy, the red deer inhabits most of Europe, the Caucasus Mountains region, Asia Minor, parts of western Asia, and central Asia. It also inhabits the Atlas Mountains region between Morocco and Tunisia in northwestern Africa, being...

available to hunters.