The Witwatersrand is a large sedimentary range of rocky hills in South Africa. Although it has an elevation of 1700–1800 metres above sea-level, it appears low because of the average height of the surrounding mountain plateau. The Witwatersrand runs in an east-west direction through Gauteng. The word in Afrikaans means "the ridge of white waters".
Geologically it is complex, but the principal formations are quartzites, conglomerates and shales of the Witwatersrand System.The Witwatersrand range forms a continental divide with rivers to the north such as the Crocodile River draining into the Limpopo River and Indian Ocean and with the run-off to the south draining into the Orange River and Atlantic.The Witwatersrand lies within the province of Gauteng, formerly called the PWV area, an acronym for Pretoria, Witwatersrand, and Vereeniging.
The rocks of the "Rand" or reef, as the Witwatersrand is sometimes known, are rich in uranium and gold. The area is famous for being the source of 40% of the gold ever mined from the earth. It extends for 280 kilometres from Klerksdorp in the west to Bethal in the east and is 4 kilometres (2.5 mi) deep in places.The South African currency was named after it. The reef's most northerly tip was discovered only a few kilometres from the present day town of Magaliesburg, at Blaauwbank, in 1874.
Witwatersrand also denotes the Greater Johannesburg Metropolitan Area, which spans the length of the gold-bearing reef.The metropolitan area is oblong in shape and runs from the area of Randfontein and Carletonville in the west to Springs in the east. It includes the vast urban areas of the East and West Rand, and Soweto.
The Witwatersrand is in the Transvaal, formerly an independent state settled by the Boers after the Great Trek. J. H. Davis, an Englishman, was reported to have found gold "in considerable quantities" in July 1852 at Paardekraal near Krugersdorp, which was the earliest discovery on the Rand.The subsequent discovery of other rich and profitable veins of gold, as well as uranium, eventually led to the creation of the largest urban conglomeration in sub-Saharan Africa.