The urban population of the world is increasing. that is why the cities are getting bigger and coming close together. Such agglomeration of two or more big cities is called megapolis
The Northeast megalopolis (also Boston–Washington corridor or Bos-Wash corridor[2]), the second most populous megalopolis in the United States with over 50 million residents, is the most heavily urbanized agglomeration of the United States. Located primarily on the Atlantic Ocean in the Northeastern United States, with its lower terminus in the upper Southeast, it runs primarily northeast to southwest from the northern suburbs of Boston, Massachusetts, to the southern suburbs of Washington, D.C., in Northern Virginia.[3] It includes the major cities of Boston, New York City, Philadelphia, Baltimore, and Washington, D.C.,[4] along with their metropolitan areas and suburbs, as well as many smaller urban centers such as Richmond and Norfolk, Virginia to the south and Portland, Maine to the north.[5]
On a map, the megalopolis appears almost as a straight line. As of 2010, the region contained over 50 million people, about 17% of the U.S. population on less than 2% of the nation's land area, with a population density of approximately 1,000 people per square mile (390 people/km2), compared to the U.S. average of 80.5 per square mile 2[6] (31 people/km2). America 2050 projections expect the area to grow to 58.1 million people by 2025.[7][8]
French geographer Jean Gottmann popularized the term in his landmark 1961 study of the region, Megalopolis: The Urbanized Northeastern Seaboard of the United States. Gottmann concluded that the region's cities, while discrete and independent, are uniquely tied to each other through the intermeshing of their suburban zones, taking on some characteristics of a single, massive city: a megalopolis.
The megalopolis' higher education network comprises hundreds of colleges and universities, including Harvard University, Princeton University, Columbia University and Yale University, which are ranked among the top 3 universities in the United States and top 10 universities in the world
Region
The megalopolis encompasses the District of Columbia and part or all of 11 states: from south to north, Virginia, Maryland, Delaware, Pennsylvania, New Jersey, New York, Connecticut, Rhode Island, Massachusetts, New Hampshire, and Maine. It is linked by Interstate 95 and U.S. Route 1, which start in Miami and Key West, Florida, respectively, and terminate in Maine at the Canada–United States border, as well as the Northeast Corridor railway line, the busiest passenger rail line in the country. It is home to over 50 million people,[7] and Metropolitan Statistical Areas are contiguous from Washington to Boston.[10] The region is not uniformly populated between the terminal cities, and there are regions nominally within the corridor yet located away from the main transit lines that have been bypassed by urbanization, such as Connecticut's Quiet Corner.