The mouth of South Africa's largest river is located on the Atlantic coast and forms the border with Namibia. As a result of its transborder position, and the fact that Namibia has also designated its part of the mouth a Ramsar site, processes are underway to declare a jointly-managed transboundary Ramsar site.

In general terms the wetland can be described as a delta type river mouth with a braided channel system during low flow months. The Ramsr site comprises sand banks or channel bars covered with pioneer vegetation, a tidal basin, a narrow floodplain, pans, the river mouth, and a salt-marsh on the south bank of the river mouth. The Orange River usually flows directly into the Atlantic Ocean but at times has its access to the sea blocked by sand-bars. It is thus not a true estuary and is best termed a river mouth.

The wetland plays an important role as one of a limited number of wetlands along the arid Atlantic coastline of southern Africa. The river mouth, mudflats, intrafluvial marshlands, islets near the mouth and adjacent pans provide a sizeable area of sheltered shallow water suitable for concentrations of wetland birds, which use these habitats for breeding purposes or as a stopover on migration routes. The bird population can be as high as 20 000 to 26 000 individuals. Of the 57 wetland species recorded, 14 are listed as either rare or endangered in one or both of the South African and Namibian Red Data Books.

At times the area supports more than 1 % of the world population of three species endemic to south-western Africa: the Cape cormorant Phalacrocorax capensis, Damara tern Sterna balaenarum and Hartlaub's gull Larus hartlaubii. On a southern Africa scale the wetland supports more than 1 % of the subcontinental population of blacknecked grebe Podiceps nigricollis, lesser flamingo Phoenicopterus minor, chestnutbanded plover Charadrius pallidus, curlew sandpiper Calidris ferruginea, swift tern Sterna bergii, and Caspian tern Hydroprogne caspia.

In 1995 the site was placed on the Montreux Record of the Ramsar Convention following the collapse of the salt marsh component of the system, which was the result of a combination of impacts, both at and upstream of the wetland. As a result of the decline in ecological character of the wetland, there has been a significant decrease in the number of waterfowl utilizing the system. Efforts are currently underway to secure statutory protected status for the site, which will enable the Northern Cape Nature Conservation Service to begin managing and rehabilitating the wetland.