The Senegal River is a vital resource for four West African countries: Guinea, Mali, Mauritania, and Senegal. Its economic, environmental, and geopolitical significance makes it a major issue for regional cooperation. This article analyzes the environmental, economic, and diplomatic dimensions of its governance by drawing on several theoretical approaches in international relations, including realism, institutional liberalism, and critical approaches. The central hypothesis is that the management of the Senegal River constitutes both a unique model of inter-state cooperation in Africa and an illustration of the constraints imposed by state sovereignty and dependence on international donors. The results show that, despite notable institutional successes, the river’s governance remains fragile and must evolve to address climate and social challenges.