Concept
The Northeast megalopolis, also known as the Northeast Corridor, Acela Corridor, Boston–Washington corridor, or BosWash, is the world's largest megalopolis in terms of economic output and the second-most populous megalopolis in the United States with approximately 50 million residents as of 2020. Located primarily on the Atlantic Coast in the Northeastern United States with its lower terminus in the upper Southeast, the Northeast megalopolis runs primarily northeast to southwest from the northern suburbs of Boston to Washington, D.C. It includes many of the nation's most populated cities, including New York City, Philadelphia, Baltimore, and others, along with their metropolitan areas and suburbs. It is sometimes defined more broadly to include urban regions beyond these, including Richmond and Hampton Roads regions to the south, Portland, Maine and Manchester, New Hampshire to the north, and Harrisburg, Pennsylvania, to the west. The Northeast megalopolis extends in a roughly straight line along a section of U.S. Route 1 and Interstate 95. 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 (31 people/km2). America 2050 projections estimate the area will grow to 58.1 million people by 2025. French geographer Jean Gottmann popularized the term megalopolis in his 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, a term he co-opted from an ancient Greek town of the same name that named itself out of aspirations to become the largest Greek city.
