The Highveld is a high plateau area of South Africa which includes the largest metropolitan area in the country, Johannesburg. The area of the Highveld is the size of Belgium, starting east of the Johannesburg center and stretching to the Swaziland border, encompassing rural and urban areas of around 4 million square kilometers. For alternate uses of the term, see Plateau (disambiguation). ... Johannesburg skyline at night with the Crown Interchange in the foreground Johannesburg is the most populous city in South Africa and the second most populous city in Sub-Saharan Africa, behind Lagos. ...