The BosWash megalopolis is the name for a group of metropolitan areas in the northeastern United States, extending from Boston to Washington and linked by economics, transport, and communications. The high-speed Amtrak train, the Acela, runs the length of the BosWash area.
BosWash contains a reported population of 44 million, or 16% of the population of the United States, and four of the world's fifty largest metropolitan areas — Boston, New York, Philadelphia, and Washington.
The geographic trend was first identified in the 1961 book Megalopolis: The Urbanized Northeastern Seaboard of the United States by French geographer Jean Gottman.
What makes you think of fast-paced life, cultural diversity, great schools, lots of traffic, four seasons, city-life, suburbia, and beaches galore all within close proximity of each other?