Niger River

The Niger River is West Africa's main river, stretching 4,180 kilometers (2,600 mi). Its drainage basin covers an area of 2,117,700 km2 (817,600 sq mi). Its source is in the Guinea Highlands, near the Sierra Leone border in southeastern Guinea. It flows in a crescent through Mali, Niger, on the border with Benin, and then through Nigeria, discharging into the Gulf of Guinea in the Atlantic Ocean through a massive delta known as the Niger Delta (or the Oil Rivers). The Niger River is Africa's third-longest river, trailing only the Nile and the Congo River (also known as the Zare River). The Benue River is its main tributary.

The Niger follows one of the most unusual routes of any major river, forming a boomerang shape that has perplexed geographers for two centuries. The river's headwaters (Tembakounda) are 240 kilometers (150 miles) inland from the Atlantic Ocean, but it flows directly away from the sea into the Sahara Desert, then takes a sharp right turn near the ancient city of Timbuktu (Tombouctou) and heads southeast to the Gulf of Guinea. This unusual geography is thought to have resulted from the Niger River's union of two ancient rivers. The upper Niger, from its headwaters west of Timbuktu to the current river's bend near Timbuktu, once flowed into a now-dry lake to the east northeast of Timbuktu, whereas the lower Niger began to the south of Timbuktu and flowed south into the Gulf of Guinea. The lower Niger's upstream erosion resulted in stream capture of the upper Niger by the lower Niger over time.

The northern section of the river, known as the Niger bend, is significant because it is the main river and source of water in that region of the Sahara. As a result, it became the focal point of trade across the Western Sahara, as well as the center of the Sahelian kingdoms of Mali and Gao. The surrounding Niger River Basin is one of the Sudan province's distinct physiographic sections, which is part of the larger African massive physiographic division.

Length: 4,184 km (2,600 mi- shared with Niger, Nigeria, Mali and Guinea)