The ǂNūǃarib (Senqu) "Black River", IGqili, or Orange River (from Afrikaans/Dutch: Oranjerivier) is a river in Southern Africa. It is the longest river within the borders of Lesotho and the Orange River Basin extends extensively into South Africa, Namibia and Botswana to the north. It rises in the Drakensberg mountains in Lesotho, flowing westwards through South Africa to the Atlantic Ocean. 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. Except for Upington, it does not pass through any major cities. The Orange River plays an important role in the South African economy by providing water for irrigation and hydroelectric power. The river was named the Orange River in honour of the Dutch ruling family, the House of Orange, by the Dutch explorer Robert Jacob Gordon. Other names include simply the word for river, in Khoekhoegowab orthography written as !Garib, which is rendered in Afrikaans as Gariep River with the intrusion of a velar fricative in place of the alveolar click, Groote River (derived from Kai !Garib) or Senqu River (used in Lesotho), derived from ǂNū "Black".