The Maputo River (Portuguese Rio Maputo), also called Great Usutu River, Lusutfu River, or Suthu River, is a river in South Africa, Swaziland, and Mozambique. The name Suthu refers to Basotho people who lived near the source of the river, but were attacked and displaced by Swazis. It is also said to mean 'dark brown', a description of the river's muddy water.
The river rises near Amsterdam, Mpumalanga, South Africa, and flows through Swaziland in an easterly direction, where it enters the Lubumbo Mountains. The 13-kilometre gorge forms the boundary between Swaziland and South Africa. For approximately twenty kilometres, it forms the border between South Africa (province of KwaZulu-Natal) and Mozambique. There, in the Ndumo Game Reserve, it absorbs its largest tributary, the Pongola River. It then meanders through the Mozambican coastal plain and empties into southern Maputo Bay, some 85 kilometres downstream.
In Swaziland, the river, there called the Great Usutu or Lusutfu, flows through the towns of Bhunya, Luyengo, Siphofaneni, and Big Bend. The town of Big Bend is located near a point in the river where it meanders abruptly. The Great Usutu is the largest river in Swaziland and the site of Swaziland's lowest point (21 meters above sea level). It is known for whitewater rafting. No large towns have been able to form along its banks due to deep narrow valleys and dense forests. It is home to some golf courses, hotels, and nature reserves, however.