The Greater Johannesburg Metropolitan Area is the area surrounding the city of Johannesburg, South Africa. It includes Johannesburg and the municipalities of Ekurhuleni and West Rand. It is often referred to as the Witwatersrand, or Rand, after a low mountain range that runs through the area. As of the 2007 Community Survey, its population was 3.9 million, but such figures can be problematic because the city is decentralized, with suburbs like Sandton now of greater economic importance than the city centre. The population of the Greater Johannesburg Metropolitan Area was 7,151,447, and including suburban regions such as Ekurhuleni, the West Rand, Soweto and Lenasia brings the overall population to 10,267,700 (as of 2007).
The municipal city's land area is very large, listed as 1,645 km2 (635 sq mi). This, however, refers fairly narrowly to the contiguous urbanized area of the city, as the metropolitan area is roughly elliptical (or oblong) in shape, with more development around the core city of Johannesburg. This greater area stretches almost 100 kilometres (62 mi) east-west from Randfontein to Nigel, and some 60 kilometres (37 mi) north-south from Midrand to Orange Farm and Vosloorus, a total area almost four times that officially stated for the metropolis, and over four times that for Greater London. It is by far the largest city in Africa in terms of physical size.
Greater Johannesburg's growth was largely based initially on the discovery of gold, and the urban area runs the length of the gold-bearing reef from east to west. In the past 30 years, there has been considerable growth to the north, as Johannesburg has expanded. Sandton, created as a separate municipal area north of Johannesburg in 1969, is where much of the new business growth has taken place.
In keeping with the definition of a metropolitan area, Johannesburg is multinodal, with several centres which are important within their own right: these include Sandton, Randburg, Midrand, Germiston, Roodepoort, Kempton Park, Boksburg, Benoni, and Springs. The urban area is often described as having an inner urban core and an outer core, with the focal point being the Johannesburg CBD.