Conurbation

A conurbation is a region consisting of a number of metropolises, cities, large towns, and other urban areas which, through population growth and physical expansion, have merged to form one continuous urban or industrially developed area. In most cases, a conurbation is a polycentric urbanised area in which transportation has developed to link areas. They create a single urban labour market or travel to work area.

Conurbations often emerged in coal-mining regions during the period of the Industrial Revolution. Patrick Geddes coined the term in his book Cities in Evolution (1915). He drew attention to the ability of the new technology at the time of electric power and motorised transport to allow cities to spread and agglomerate together, and gave as examples "Midlandton" in England, the Ruhr in Germany, Randstad in the Netherlands, and the Northeastern Seaboard in the United States.

For census purposes, the term as described is used in Britain, whereas in the United States a related concept of metropolitan area is used instead. Each polycentric "metropolitan area" may have its own common designation such as San Francisco Bay Area or the Dallas–Fort Worth metroplex. Internationally the term "urban agglomeration" is often used to convey a similar meaning to "conurbation".

A conurbation is different from a megalopolis in that the urban areas of a megalopolis are close but not physically contiguous, and labor markets have not yet merged. The region structure should also be contrasted with a megacity, as a megacity is hierarchical with a dominant urban core, whereas a conurbation is polycentric and no single urban centre has the dominant role over all other centres.

The capital cities of Kinshasa in the Democratic Republic of the Congo and Brazzaville in the Republic of the Congo form a conurbation.

In Rabat-Salé-Kénitra administrative region, the capital city of Rabat and the city of Salé, both located at the mouth of the river Bou Regreg, form a conurbation.

Lagos is a conurbation formed through the merged development of the initial Lagos city area with other cities and towns including Ikeja and Ojo. Also various suburban communities such as Agege, Alimosho, Ifako-Ijaiye, Kosofe, Mushin, Oshodi, and Shomolu are included in the area.

Johannesburg, Ekurhuleni (East Rand), and Tshwane (greater Pretoria) merged to form a region that has a population of 14.6 million.