With a length of 650 kilometres the Fish River is the longest river in Namibia. Its source lies in the eastern Naukluft Mountains. South-west of Ai-Ais it flows into the Oranje.

The Fish River canyon, situated along the lower reaches of the Fish River, is one of the most impressive natural beauties in the southern part of Namibia. With a depth of up to 550 metres, the Fish River Canyon is the second largest canyon in the world. The enormous gorge meanders along a distance of approx. 160 kilometres through the fissured Koubis massif all the way down to Ai-Ais. The canyon starts near Seeheim. It is 161 kilometres long and ends at Ai-Ais.
 

Bordering the canyon's eastern rim is the privately owned Gondwana Cañon Park, a 102 000 ha stretch of land that is managed as a nature park. In earlier times this land was used for sheep farming. However, as it lies in a semi-desert area, it was soon proven to be unsuitable for farming. Existing fences have been removed and water points established for the game.

The Fish River Hiking Trail, often compared in terms of difficulty to the daunting Otter Trail in South Africa, ranks amongst the Big Five hiking trails in the Southern African Region.