The Atbarah River, also referred to as the Red Nile and / or Black Nile, is a river in northeast Africa. It rises in northwest Ethiopia, approximately 50 km north of Lake Tana and 30 km west of Gondar. It then flows about 805 km (500 mi) to the Nile in north-central Sudan, joining it at the city of Atbarah. The river's tributary, the Tekezé (Setit) River, is perhaps the true upper course of the Atbarah, as the Tekezé follows the longer course prior to the confluence of the two rivers in northeastern Sudan. The Atbarah is the last tributary of the Nile before it reaches the Mediterranean.

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 6,650 km (4,130 mi) long, its drainage basin covers eleven countries: the Democratic Republic of the Congo, Tanzania, Burundi, Rwanda, Uganda, Kenya, Ethiopia, Eritrea, South Sudan, 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.