The Nile flows through Cairo and forms the Nile Delta, the largest river delta in the Mediterranean region.
The river runs northward through northeastern Africa before entering the Mediterranean Sea. Its two principal modern tributaries are the White Nile, whose headwaters lie in the Great Lakes region, and the Blue Nile, which rises in Ethiopia. They meet at Khartoum in Sudan, after which the combined river continues through Egypt.
The Nile Delta begins north of Cairo, where the river divides into the Rosetta and Damietta branches. The triangular lowland is intensely cultivated because its alluvial soils were historically renewed by annual floods. The Aswan High Dam, completed in the 1970s, greatly changed the river's flood and sediment patterns.
Ancient Egyptian civilization depended on the Nile for water, transport, farming, and communication. The river is sometimes described as the world's longest, although exact rankings depend on how the Nile and Amazon systems are measured.