The Kagera River, also Akagera River, is an East African river, forming part of the upper headwaters of the Nile and carrying water from its most distant source.
The section of river named Kagera begins in Burundi, flowing out from Lake Rweru. From the lake, it flows east along the Rwanda-Burundi and Rwanda-Tanzania borders to a confluence with the Ruvubu River. The waters of the Kagera are thus provided by two major tributaries, the Nyabarongo of Rwanda, which feeds Lake Rweru, and the Ruvubu of Burundi. It is unknown which of these two feeder rivers is the longer and hence the ultimate source of the Nile. From the confluence, the Kagera flows north along the Rwanda-Tanzania border, over Rusumo Falls and through Akagera National Park. It then takes a turn to the east, following the Tanzania-Uganda border and emptying into Lake Victoria in Uganda.
The river has featured prominently in the histories of the countries it runs through, particularly Rwanda. In 1894, German Gustav Adolf von Götzen crossed the Kagera at Rusumo Falls, beginning the Rwandan colonial era; and in 1916, during World War I, the Belgians defeated the Germans, entering Rwanda by the same route. The river gained international notoriety in 1994 for carrying bodies from the Rwandan Genocide into Lake Victoria, causing a state of emergency to be declared in areas of Uganda, where these bodies eventually washed up.