The Nile flows through Cairo and forms the famous Nile Delta in northern Egypt.
The Nile runs northward through northeastern Africa before entering the Mediterranean Sea. Its two principal tributaries are the White Nile, whose farthest headwaters are in the Great Lakes region, and the Blue Nile, which rises in Ethiopia and supplies much of the river’s seasonal sediment and flow.
Cairo stands on the river near the southern edge of the Nile Delta. North of the city, the river divides into distributaries and spreads across fertile lowlands before reaching the Mediterranean. The delta’s shape resembles the Greek letter delta, which is why the geographic term is used for many river mouths.
For thousands of years, Egyptian agriculture depended on the Nile’s flood cycle. The Aswan High Dam, completed in the 1970s, greatly reduced annual flooding and created Lake Nasser, while also trapping much of the sediment that once naturally renewed downstream soils. The Nile’s exact status as the world’s longest river is debated with the Amazon, but its central role in Egyptian civilization is undisputed.