The Sobat River is a river of the Greater Upper Nile region in northeastern South Sudan, Africa. It is the most southerly of the great eastern tributaries of the White Nile, before the confluence with the Blue Nile.

Geography

The Sobat River is formed by the confluence of the west-flowing Baro River and the north-flowing Pibor River, on the border with Ethiopia. The river enters the White Nile at Doleib Hill, near the city of Malakal in Upper Nile State. When in flood the Sobat River produces an enormous discharge carrying a white sediment, which gives the White Nile its name.

Hydrology

The Sobat and its tributaries drain a watershed approximately 225000 km2 in size. The river's mean annual discharge is 412 m³/s (14,550 ft³/s).