Johannesburg is the most populous city and the commercial capital of South Africa. It was founded in 1886, following the discovery of gold, and was initially part of the Transvaal, an independent Afrikaner republic that later became one of the four provinces of South Africa.

Today, the city is the capital of Gauteng, the wealthiest province in South Africa.

Located in north-central South Africa, Johannesburg is the country's largest and fastest-growing city and one of the 50 largest urban areas in the world.

Johannesburg is situated on the highveld plateau, and has a subtropical highland climate.

According to the 2011 South African National Census, the population of Johannesburg is 4,434,827 people, making it the most populous city in South Africa

• Johannesburg's nickname "eGoli" ("city of gold") evokes the city’s origin as a mining town in the late nineteenth century.
  Population heritage: Blacks account for 73% of the population, followed by whites at 18%, coloureds at 6% and Asians at 4%.
  42% of the population is under the age of 24.
• Language: 32% of Johannesburg residents speak Nguni languages at home, 24% speak Sotho languages, 18% speak English, 7% speak Afrikaans and 6% speak Tshivenda.
• Currency: Johannesburg uses the South African Rand.
   

South Africa possesses a federal system of government, with authority divided between national, provincial, and local levels of government.

Greater Johannesburg has a multilevel system of popularly elected local government that has been in place since November 1955. The local authority rests with the City of Johannesburg Metropolitan Municipality, which includes representatives from all across the metropolitan area to include the surrounding black townships in the political process.

At the highest level, there is the Greater Johannesburg Metropolitan Board, a metropolitan council that oversees the distribution of municipal resources. Next there are four local councils that handle city services within their communities. The local councils are divided into wards, each of which has its own elected representative. In addition to voting for individual representatives from their wards, residents also vote for the party of their choice in elections for both the local and municipal councils.

Johannesburg is also the legislative capital of Gauteng Province formerly called the Pretoria-Witwatersrand-Vaal triangle.

Johannesburg is South Africa's major commercial, financial, and industrial center, producing 16% of South Africa's gross domestic product, and accounts for 40% of Gauteng's economic activity.

It is home to the South African stock exchange, the leading banks, the country's mining companies, the Chamber of Mines, and the government regulatory agency in charge of mining

Mining was historically the foundation of the Witwatersrand's economy, but its importance has gradually declined. While gold mining no longer takes place within the city limits, most mining companies still have their headquarters in Johannesburg.

Nowadays, service and manufacturing industries have become more significant to the city's economy. Johannesburg is a major manufacturing center whose factories produce a wide range of goods from steel to textiles. Other industries growing importance include banking, IT, real estate, transport, broadcast, private health care and transport. South Africa's major insurance, retail, engineering, and construction companies are also located in the city.

Johannesburg has not traditionally been known as a tourist destination, but the city is a transit point for connecting flights to Cape Town, Durban, and the Kruger National Park. Consequently, most international visitors to South Africa pass through Johannesburg at least once, which has led to the development of more attractions for tourists.

The city is also home to some 10,000 to 12,000 street traders whose operations in the central business district bring in an annual combined revenue of some 500 million rand.

The Johannesburg area has a well-developed highway system that carries thousands of commuters between the city and its suburbs every day. However the city is quite young and its public transportation lacks a convenient public transportation system. The city has invested a large percentage of its budget toward an effective integrated public transportation system.

The Metrorail Gauteng commuter rail system connects central Johannesburg to Soweto, Pretoria, and most of the satellite towns along the Witwatersrand. However, it covers only the older areas in the city's south. The northern areas, including the business districts of Sandton, Midrand, Randburg, and Rosebank, are served by the rapid rail link Gautrain.

Airports
Johannesburg is served principally by OR Tambo International Airport for both domestic and international flights to cities in Europe, Asia, Australia, and the Western Hemisphere. This airport is located around 20 kilometres east of the city. International air traffic to Johannesburg has increased greatly since the lifting of foreign embargoes against South Africa in early 1990s, and major renovations of the airport are underway.

Another airport option is Lanseria Airport, located to the north-west of the city and closer to the business hub of Sandton. This hub is used for commercial flights to Cape Town, Durban, Port Elizabeth, Botswana, and Sun City.