The term toshiken (, metropolitan area in Japanese) refers to a metropolitan area in Japan. The Greater Tokyo Area is a major metropolitan area in the nation, consisting of the Kant region of Japan, including the Tokyo Metropolis, as well as Yamanashi Prefecture.
The concept of a "megalopolis" was first examined in detail by the Scottish geographer Patrick Geddes in his 1915 book Cities in Evolution. Geddes describes it as a "city-region", a chain of interlinked urban or metropolitan areas.
One prominent North American example of a megalopolis is the Northeast megalopolis, sometimes called the BosWash after the cities on either end: it consists of Boston; Providence, RI; Hartford, CT; Greater New York City; Philadelphia; Wilmington, DE; Baltimore; Washington, DC and their vicinities. Two other prominent megalopolises in North America are as follows:
In California and Baja California, Ventura County, Los Angeles County, Orange County, San Diego County, part of Riverside County, part of San Bernardino County, Tijuana Municipality, Rosarito Beach Municipality, Mexicali Municipality, and Tecate Municipality. There are hundreds of cities and towns in this megalopolis, with the largest ones being Los Angeles, Long Beach, Irvine, Anaheim, San Diego, and Tijuana.
The bi-national Great Lakes Megalopolis consists of the group of North American metropolitan areas surrounding the Great Lakes region within the Midwestern United States, Southern Ontario, and parts of Pennsylvania, New York, and Quebec. The region extends from the MilwaukeeChicagoGary corridor to the DetroitToronto corridor, and includes Buffalo, Cincinnati, Cleveland, Columbus, Dayton, Erie, Grand Rapids, Indianapolis, Louisville, Ottawa, Rochester, and Toledo, reaching as far as Pittsburgh and St. Louis. The region had an estimated population of 54 million for the 2000 Census and is projected to reach about 65 million by 2025, although much of this area has remained rural, due in part to the decline of the Rust Belt.
The world's largest megalopolis is probably the Taiheiy Belt (the Pacific megalopolis) of Japan on southeastern Honshu that consists of the metropolis of Tokyo, Kawasaki, Yokohama, Shizuoka, Hamamatsu, Nagoya, Kyoto, Osaka, Kobe, Okayama, Hiroshima, Kitakyushu, Fukuoka and their surrounding cities and towns. Major means of ground transportation in Japan such as its railroad network (for both passengers and freight), many expressways, and the "Shinkansen" bullet train are concentrated in this region, which also includes the northern shore of the Inland Sea of Japan. This is a highly industrialized part of Japan, and it is also the location of its most important seaports in Japan such as at Yokohama, Osaka, Kobe, Hiroshima and Kure and its most important international airports such as at Tokyo and Osaka. The population of this megalopolis can be as high as 83 million people, depending on where one draws its boundaries.
Seoul National Capital Area is a megalopolis with a population of 24 million, which includes Seoul, Incheon, Suwon, Goyang and the rest of Gyeonggi-do and extends to some fraction of western Gangwon-do, and Chungcheong-do. Its area is over 10,000 and about 11,745, which is connected by ground transportation such as its railroad network, many expressways, and High-speed rail so-called "KTX".
Guangdong Province's Pearl River Delta is a megalopolis with a population of 48 million that extends from Hong Kong and Shenzhen to Guangzhou. Some projections assume that by 2030 up to 1 billion people will live in China's urban areas. Even rather conservative projections predict an urban population of up to 800 million people. In its most recent assessment, the UN Population Division estimated an urban population of 1 billion in 2050.
Europe contains numerous large metropolitan areas, such as the Madrid metropolitan area in Spain (pop. 6.3 million), the Milan metropolitan area (pop. 8 million) in Italy, the Barcelona metropolitan area (pop. 5 million), the Randstad (pop. 7.1 million) in the Netherlands, the Upper Silesian metropolitan area (pop. 7 million) in Poland and the Czech Republic, and the Flemish Diamond (pop. 5.5 million) in Belgium. The largest are the London metropolitan area (pop. 13.6 million), Paris metropolitan area (pop. 12.2 million), and the Rhine-Ruhr metropolitan region (pop. 11.5 million) in Germany. However, it is generally considered only to contain one megalopolis, best known as the 'Blue Banana'. The concept was developed in 1989 by Frenchman Roger Brunet. Its precise extent is not universally agreed, but it typically stretches from London and the Thames estuary down the Rhine corridor including the likes of Brussels, Paris and the Rhine-Ruhr as far as Turin and Milan. Assessments of the total population range from 92 to 110 million, depending on the inclusion of the Parisian area which was most explicitly excluded by Brunet. It has been subject to criticism, particularly due to the discontinuity caused by the very low-population areas of the Alps and the North Sea; alternative models have also been suggested, such as the overlapping Golden Banana, and an emerging English megalopolis comprising most of southeastern England, the Midlands and parts of northern England. Indeed, using the criterion of population density, England as a whole already has a population density of 407 people per square kilometre, which is higher than the United States Northeast megalopolis.
Africa's first megalopolis is 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.
Brazil has one megalopolis: the Rio de JaneiroSo Paulo Megalopolis, which includes parts of Minas Gerais, Rio de Janeiro and So Paulo states and has a population of over 45 million inhabitants. It spreads throughout much of the Southeast Region of the country, a conurbation that brings together more than 450 cities defined primarily by metropolitan areas of Rio de Janeiro and So Paulo and the whole catchment area around and between them (separated by about 300 km) is by far the most urbanized and industrialized in the country and Latin America.
Megacity is a general term for metropolitan areas that usually have a total population in excess of ten million people. In Canada, "megacity" can also refer 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 urbanized area, since many of its named "cities" have both rural and urban portions. Also, 10 million inhabitants is an unreasonably high number for Canada. Moreover, Canadian "megacities" do not constitute large metropolitan areas in a global sense. For example, Toronto has a metropolitan population of about five million people, but is part of a much larger metropolitan region called the Golden Horseshoe, which has about eight million people.
The census population of a metro area is not the city population. However, it better demonstrates the population of the city. Los Angeles may only have a city population of slightly less than four million, but depending on the definition, it has a metropolitan area population of either 13 million, or 18 million people in its combined statistical area. A major question is whether or not to include San Diego and Tijuana.