The Nile is the major river that flows through the Sahara Desert and reaches the Mediterranean Sea. Its valley and delta form a long, fertile corridor through northeastern Africa.
The river runs northward through countries including Uganda, South Sudan, Sudan and Egypt. In Sudan and Egypt, the surrounding landscape is overwhelmingly arid, so the Nile supports dense settlement and agriculture in an otherwise extremely dry region.
The Nile is traditionally described as the world’s longest river, although comparisons with the Amazon depend on how river sources and mouths are measured. Its two principal tributaries are the White Nile and Blue Nile; they meet at Khartoum in Sudan.
The Nile does not make the entire Sahara fertile. Instead, its water is concentrated in a narrow valley and delta. This distinctive contrast between green cultivated land and surrounding desert is one of the defining geographic features of Egypt and northern Sudan.