It floods the flatland of the south to form a vast swamp called the Sudd. North of the Sudd, the Bahr al Jabal is called the White Nile. It meets the Blue Nile, which flows from the mountains of Ethiopia, at Khartoum. Together, the two rivers form the main Nile River. North of Khartoum, Sudan is primarily desert.
People live along the banks of the Nile and the Red Sea, but much of northern Sudan is uninhabited.
A few nomadic groups travel with herds of camels near the southern edge of the region and in the Red Sea Hills in the east. Northern Sudan Central Sudan consists largely of a grass-covered plain. Farmers also grow crops in an upland area in the west, in the Nuba Mountains along the White Nile, and in an irrigated clay plain in the east. Most of southern Sudan consists of a flood plain formed by the branches of the Nile River. Dense, junglelike vegetation covers much of the region.