|Name origin: From the Swazi language word for "cow", meaning hippos|
|Countries||South Africa, Swaziland, Mozambique|
|- location||Near Ermelo, Mpumalanga|
|- elevation||1,800 m (5,906 ft)|
|- location||Maputo Bay|
|Length||480 km (298 mi)|
|Basin||50,000 km2 (19,305 sq mi)|
|- average||111 m3/s (3,920 cu ft/s)|
The Komati River (also called Incomati River) is a river in South Africa, Swaziland and Mozambique. It is 480 kilometres (298 mi) long, with a drainage basin 50,000 square kilometres (19,300 sq mi) in size. Its mean annual discharge is 111 m³/s (3,920 cfs) at its mouth. The name Komati is derived from inkomati (siSwati), meaning "cow", as its perennial nature is compared to a cow that always has milk.
The river originates west of Carolina, rising at an elevation of about 5,906 feet (1,800 m) near Breyten in the Ermelo district of the Mpumalanga province. It flows in a general northeasterly direction and reaches the Indian Ocean at Maputo Bay, after a course of some 480 kilometres (298 mi). The Komati Gorge is situated in the upper reaches of the Komati River and is the habitat of some endangered species such as the Southern Bald Ibis. In 2001 the 115 m high wall of the Maguga Dam was completed south of Piggs Peak, Swaziland, .
In its upper valley near Steynsdorp are goldfields, but the reefs consist almost entirely of low grade ore. The river descends the Drakensberg by a pass 30 miles (48 km) south of Barberton, and is deflected northward at the eastern border of Swaziland, keeping a course parallel to the Lebombo mountains. Just west of 32°E and 25°25'S, near the town of Komatipoort, it is joined by the Crocodile River. The Crocodile tributary rises, as the Elands River, in the Bergendal (1,961m) near the upper waters of the Komati, and flows eastwards across the highveld, being turned northward as it reaches the Drakensberg escarpment. The fall to the lowveld is over 600 m in 30 miles (48 km), and across the 100 miles (161 km) wide country between the Drakensberg and the Lebombo there is a further fall of 900 m.
Just over a kilometre below the junction of the Crocodile, the united stream, which from this point is also known as the Manhissa, passes to the coastal plain through a 190 m high cleft, high in the Lebombo known as Komatipoort, featuring some picturesque falls. At Komatipoort, which marks the border between South Africa and Mozambique, the river is less than 60 miles (97 km) from its mouth in a direct line, but in crossing the plain it makes a wide sweep of 200 miles (322 km), first northwards before turning southwards, forming lagoon-like expanses and backwaters and receiving from the north several tributaries. In flood time there is a connection northward through the swamps with the basin of the Limpopo. The Komati enters the sea 15 miles (24 km) north of Maputo. It is navigable from its mouth, where the water is up to 5m deep, to the foot of the Lebombo.
The Portuguese named the river's lower reaches the Rio des Reijs, or "river of rice". Subsequently Jan van Riebeeck's journal mentions a Rio de Reijs, when he dispatched a ship up the east coast in search of rice supplies. In voortrekker Louis Tregardt's journal it is referred to as the Manhissa, a name still extant, while to the British it was known as the King George River.
In 1725 a Dutch expedition led by Francois de Kuiper explored the region of the lower Komati and travelled 30km into the current Mpumalanga province, before they were attacked by local tribes and had to return to Delagoa Bay.
On the September 23, 1900 during the Second Boer War, 3,000 Boers crossed the frontier at the small town of Komati Poort, and surrendered to the Portuguese authorities. On November 7, 1900 the banks of the Komati became the site of a battle between the British Empire and the Boers. The Battle of Leliefontein was a retreat by the British, harassed by the Boers, who were threatening to capture the British Artillery. The British guns were saved by the Royal Canadian Dragoons who charged the Boers, whereby they placed the guns out of their reach.
The railway from Maputo to Pretoria traverses the plain in a direct line, and at seventy-two kilometres, reaches the Komati. It follows the south bank of the river and enters the high country at Komati Poort. From the Poort westward the railway skirts the south bank of the Crocodile River throughout its length.
 See also
- Nakayama, Mikiyasu (2003). International Waters in Southern Africa. United Nations University Press. p. 9. ISBN 92-808-1077-4.; online at Google Books
- du Plessis, E.J. (1973). Suid-Afrikaanse berg- en riviername. Tafelberg-uitgewers, Cape Town. p. 251. ISBN 0-624-00273-X.
- "Komati River" Online Encyclopædia Britannica
- C. Michael Hogan and Amy Gregory, Ecology of Komati Gorge, July 22, 2006
- Thom, H.B. (1952). Journal of Jan van Riebeeck. A.A. Balkema, Cape Town. p. 243.
- Preller, G.S. (1938). Dagboek van Louis Trichardt. Nas. Pers Bpk., Cape Town. p. 334, footnote.
- Robertson, J.W. Traveller's Guide for South Africa. The Standard Printing Co., East London. p. VIII.