A metropolitan area is a large population center consisting of a large city and its adjacent zone of influence, or of several neighboring cities or towns and adjoining areas, with one or more large cities serving as its hub or hubs.

A metropolitan area usually combines an agglomeration (the contiguous built-up area) with peripheral zones not themselves necessarily urban in character but closely bound to the centre by employment or commerce; these zones are also sometimes known as a commuter belt, and may extend well beyond the urban periphery depending on the definition used.

The core cities in a polycentric metropolitan area need not be physically connected by continuous built-up development, distinguishing the concept from conurbation, which requires urban contiguity. In an metropolitan area, it is sufficient that central cities together constitute a large population nucleus with which other constituent parts have a high degree of integration.

The term metropolitan area is sometimes abbreviated to 'metro', for example in Metro Manila and Washington, DC Metro Area, and then should not be mistaken to mean the metro rail system of the city. In France the term for a metropolitan area is an aire urbaine.

In Japan, individual cities form metropolitan areas or conurbations such as the capital zone of Tokyo-Kawasaki-Yokohama (the Keihin area) or Osaka-Kobe, with which Kyoto is sometimes included as part of the wider Keihan zone.

If several metropolitan areas are located in succession, metropolitan areas are sometimes grouped together as a megalopolis. A megalopolis consists of several interconnected cities (and their suburbs), between which people commute, and which are so close together that suburbs can claim to be suburbs of more than one city.

This concept was first proposed by the French geographer Jean Gottmann in his book Megalopolis, a study of the northeastern United States. One famous example is the BosWash megalopolis consisting of Boston, Hartford, New York City, Philadelphia, Baltimore, Washington, and vicinity. Other megalopoleis are Tokyo and Osaka, the Ruhr Area and parts of the Low Countries. Africa's first megalopolis is said to be situated in the urban portion of Gauteng Province in South Africa, comprising the conurbation of Johannesburg, and the metropolitan areas of Pretoria and the Vaal Triangle, otherwise known as the PWV. It has been suggested that the whole of south-eastern, Midland and parts of northern England will evolve into a megalopolis dominated by London. Clearly when usage is stretched this far, it is remote from the traditional conception of a city.

Megacity is a general term for agglomerations or metropolitan areas usually with a total population in excess of 10 million people. In Canada, megacity refers informally to the results of merging a central city with its suburbs to form one large municipality. A Canadian "megacity", however, is not necessarily an entirely urban area, as many cities so named have both rural and urban portions, and do not necessarily constitute a large metropolis. Their definition is thus close to the metropolitan area concept.

See also

• Megacity
• Metroplex
• Ecumenopolis
• United States metropolitan areas
• List of metropolitan areas by population
• List of the largest urban areas of the European Union by population
• Largest European metropolitan areas
• List of fifteen largest metropolitan areas of France by population
• Metropolitan areas in ROC (Taiwan)
• Metropolitan Regions of Norway
• Metropolitan Areas of Sweden
• Metropolitan Areas of Mexico
• Census Metropolitan Area (Canada)
• List of the 100 largest metropolitan areas in Canada
• Largest metropolitan areas in the Americas

External links

• metropolis.org - An organisation of world metropolises
• Metropolitan areas - List of all 1M+ unhabitants metropolitan areas in the world