[6] The river originates west of Carolina, rising at an elevation of about 1,800 m (5,906 ft) near Breyten in the Ermelo district of the Mpumalanga province.

The river descends the Drakensberg by a pass 48 km (30 mi) south of Barberton, and is deflected northward at the eastern border of Eswatini, keeping a course parallel to the Lebombo mountains.

The Crocodile tributary rises, as the Elands River, in the Bergendal (1,961 m) near the upper waters of the Komati, and flows eastwards across the highveld, being turned northward as it reaches the Drakensberg escarpment.

[10] 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.

[11] In voortrekker Louis Tregardt's journal it is referred to as the Manhissa,[12] a name still extant, while to the British it was known as the King George River.

[13] In 1725 a Dutch expedition led by Francois de Kuiper explored the region of the lower Komati and travelled 30 km into the current Mpumalanga province, before they were attacked by local tribes and had to return to Delagoa Bay.