The Nile is the longest river system in the world. It flows 6,695 km from a source in Burundi to its mouth at the Delta in Egypt. The Nile drains 2,978 million sq km, almost one tenth of the land area of Africa. Although it is the longest river in the world, the drainage basin of the Nile is only the fourth largest (after the Amazon, Mississippi, and Congo), and at least 32 major rivers carry more water in the course of a year.