The lowest point is at Komati Poort, a gorge through the Lebombo hills only 476 ft.
Of these the Komati (q.v.) and its affluents, and the Pongola and its affluents rise in the high veld and flowing eastward to the Indian Ocean drain but a comparatively small area of the province, of which the Pongola forms for some distance the south-eastern frontier.
The Vaal (q.v.) rises in the high veld in the Ermelo district not far from the source of the Komati and that of the Usuto tributary of the Pongola.
In 1890 the construction of the Transvaal section of the railway to connect Pretoria with Delagoa Bay was begun, the line from Lourenco Marques having been completed to Komati Poort in December 1887.
This line was continued (1910) north-west to effect a junction with (6) the " Selati " railway, which, starting from Komati Poort, runs north-west and was in 1910 continued to Leydsdorp. North of the junction with the Pietersburg line the railway goes towards the Limpopo.
The total production (including the Komati and Swaziland fields) to the end of 1908 was 1,097,685 oz.
The second, the period of Boer organized resistance, may be said to have finished with the occupation of Komati Poort in October 1900 (a month after Lord Roberts's formal annexation of the Transvaal) and the flight of President Kruger.
On the 30th of May President Kruger fled with the state archives, taking up his residence at Waterval Boven on the Komati Poort line.
Before this Lord Roberts had initiated a movement from Pretoria to sweep down to Komati Poort on the Portuguese frontier, in which Buller, advancing across country from the south, was to co-operate.
By French, and on the 25th Komati Poort by Roberts's infantry.