Orange river is the longest river of South Africa . Orange river falls into Atlantic Ocean. It flows from east to west in South Africa.
The river forms part of the international borders between South Africa and Namibia and between South Africa and Lesotho, as well as several provincial borders within South Africa. Although the river does not pass through any major cities, it plays an important role in the South African economy by providing water for irrigation, mining, industrial and municipal use, as well as hydroelectric power.
The Vaal River basin, part of the broader Orange River basin, is the industrial heartland of South Africa, producing more than 25 percent of the country’s gross domestic product (GDP).
The Orange River has a total length of 1,367 miles (2,200 km). It rises in the Drakensberg mountains in Lesotho, about 120 miles (193 km) west of the Indian Ocean and at an altitude of over 3000 m. While in Lesotho, the river is known as the Senqu, and parts of it freeze in winter because of the altitude there.
The river then runs westward, forming the southwestern boundary of the Free State Province. In this section the river flows over the Gariep Dam (the largest in the country) and on to the Vanderkloof Dam.
From the border of Lesotho to below the Van der Kloof Dam the river bed is deeply incised. Farther downstream the land is flatter, and the river is used extensively for irrigation.
At the western point of the Free State, southwest of Kimberley, the Orange meets with its main tributary, the Vaal River, which itself forms much of the northern border of the province. From here the river flows through the arid wilderness of the southern Kalahari region and Namaqualand in the Northern Cape Province to meet with Namibia. As it flows west, it forms the international border between the province and Namibia’s Karas Region.