The Nile is a major north-flowing river in northeastern Africa. It flows into the Mediterranean Sea. The Nile is the longest river in Africa and has historically been considered the longest river in the world, though this has been contested by research suggesting that the Amazon River is slightly longer. Of the world's major rivers, the Nile is one of the smallest, as measured by annual flow in cubic metres of water. About long, its drainage basin covers eleven countries: the Democratic Republic of the Congo, Tanzania, Burundi, Rwanda, Uganda, Kenya, Ethiopia, Eritrea, South Sudan, Republic of the Sudan, and Egypt. In particular, the Nile is the primary water source of Egypt, Sudan and South Sudan. Additionally, the Nile is an important economic river, supporting agriculture and fishing.
The Nile has two major tributaries – the White Nile and the Blue Nile. The White Nile is traditionally considered to be the headwaters stream. However, the Blue Nile is the source of most of the water of the Nile downstream, containing 80% of the water and silt. The White Nile is longer and rises in the Great Lakes region. It begins at Lake Victoria and flows through Uganda and South Sudan. The Blue Nile begins at Lake Tana in Ethiopia and flows into Sudan from the southeast. The two rivers meet at the Sudanese capital of Khartoum.
The northern section of the river flows north almost entirely through the Nubian Desert to Cairo and its large delta, and the river flows into the Mediterranean Sea at Alexandria. Egyptian civilization and Sudanese kingdoms have depended on the river and its annual flooding since ancient times. Most of the population and cities of Egypt lie along those parts of the Nile valley north of the Aswan Dam. Nearly all the cultural and historical sites of Ancient Egypt developed and are found along river banks. The Nile is, with the Rhône and Po, one of the three Mediterranean rivers with the largest water discharge.
The standard English names "White Nile" and "Blue Nile" refer to the river's source, derived from Arabic names formerly applied to only the Sudanese stretches that meet at Khartoum.