The Northeast megalopolis, also known as the Northeast Corridor, Acela Corridor,After the Amtrak train lines connecting its cities, viz. , , Boston–Washington corridor, BosWash, Bos–Wash corridor or BosNYWash, is the most populous megalopolis exclusively within the United States, with slightly over 53 million residents as of 2024. The nickname "BosWash" for the region was first used by futurist Herman Kahn in a 1967 essay. It is the world's largest megalopolis by economic output.

Located primarily on the Atlantic Coast in the Northeastern United States, the Northeast megalopolis extends from the northern suburbs of Boston to Washington, D.C., running roughly southwesterly along a section of U.S. Route 1, Interstate 95, and the Northeast Corridor train line. It is sometimes defined more broadly to include other urban regions, including the Richmond and Hampton Roads regions to the south; Portland, Maine, and Manchester, New Hampshire, to the north; and Harrisburg, Pennsylvania, to the west. The coastal waters of the Northeast megalopolis constitute one of the fastest-warming urban ocean shorelines in the world.

The region includes many of the nation's most populated metropolitan areas, including those of New York City, Philadelphia, Washington, D.C., Boston, and Baltimore. As of 2024, it contained more than 53 million people, about 15% of the U.S. population on less than 2% of the nation's land area, with a population density of about 946 people per square mile (365 people/km2), far more than the U.S. average of 80.5 per square mile (31 people/km2). At least one projection estimates the area will grow to 58.1 million people by 2050.

Before the term megalopolis became widely used, Walter Hedden identified the growing interdependence of large cities in the Northeast in his 1929 book, specifically regarding the sourcing of milk. French geographer Jean Gottmann then 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.

Region The Northeast megalopolis includes many of the financial and political centers of influence in the United States, including the national capital of Washington, D.C., and all or part of 12 states (from north to south): Maine, New Hampshire, Massachusetts, Rhode Island, Connecticut, New York, New Jersey, Pennsylvania, Delaware, Maryland, West Virginia, and Virginia. Of all the states that traditionally make up the American Northeast, only rural, landlocked and very rugged Vermont is considered to be distinct from the more populated coastal states of the megalopolis, while Maryland and Virginia are integral to the corridor, despite being in the Southern United States. All major cities of the megalopolis are linked by Interstate 95 and U.S. Route 1, which start in Miami and Key West, Florida, respectively, in the south, and terminate in Maine at the U.S.-Canadian border. It is also linked by the Northeast Corridor train line, the country's busiest passenger rail line, serving Amtrak and several commuter rail agencies. The development of the interconnected urban corridor in the Northeast initially followed the strategic placement of these rail lines, forming a "railroad spine" before the expansion of the highway systems (such as I-95 and Route 1) and overlapping suburban areas.

As of 2019, the region is home to 52.3 million people, and its metropolitan statistical areas are contiguous from Washington, D.C., in the south to Boston in the north. 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 the Quiet Corner in Connecticut.

The region accounts for over 20% of the U.S. gross domestic product. It is home to two of the world's largest stock exchanges, the New York Stock Exchange and Nasdaq, and the headquarters of the United Nations in New York City, and the executive, legislative, and judicial centers of the U.S. federal government, the White House, the U.S. Capitol, and the U.S. Supreme Court in Washington, D.C. The region also is home to the headquarters of most of the nation's and some of the world's largest media organizations, including ABC, NBC, CBS, NPR, PBS, Fox, Comcast, The New York Times Company, USA Today, the New York Post, The Wall Street Journal, Newsday, The Washington Post, and The Boston Globe.

The global headquarters of many major financial firms, including JPMorgan Chase, Citigroup, Goldman Sachs, Morgan Stanley, Fannie Mae, Freddie Mac, Capital One, The Vanguard Group, and Fidelity, are located in the region. Among the world's 500 largest companies, 54 are based in the Northeast megalopolis. Among the 500 largest U.S.-based companies, 162 are headquartered in the region. The region is the center of the global hedge fund industry, which is heavily based in New York City and the suburban Connecticut cities of Greenwich and Stamford.

The Northeast megalopolis is home to hundreds of colleges and universities, including several that rank among the world's most elite universities, including Harvard and MIT, both in Cambridge, Massachusetts, Brown in Providence, Rhode Island, Yale in New Haven, Connecticut, Columbia in New York City, Princeton in Princeton, New Jersey, the University of Pennsylvania in Philadelphia, Johns Hopkins in Baltimore, and Georgetown in Washington, D.C.

Population

+Largest combined statistical areas (CSAs) within the Northeast megalopolis Rank(U.S.) Combined statistical area(CSA) 2020census 2010census Change1New York–Newark, NY–NJ–CT–PA3Washington–Baltimore–Arlington, DC–MD–VA–WV–PA7Boston–Worcester–Providence, MA–RI–NH–CT9Philadelphia–Reading–Camden, PA–NJ–DE–MD26New Haven-Hartford-Waterbury, CT35Virginia Beach–Chesapeake, VA–NCTotal +Largest metropolitan statistical areas (MSAs) within the Northeast MegalopolisExcerpted from Table of United States Metropolitan Statistical Areas2020 RankMetropolitan statistical area(MSA)2020 Census2010 CensusChange1New York–Newark–Jersey City, NY-NJ MSA2Washington–Arlington–Alexandria, DC-VA-MD-WV MSA3Philadelphia–Camden–Wilmington, PA-NJ-DE-MD MSA4Boston–Cambridge–Newton, MA-NH MSA5Baltimore–Columbia–Towson, MD MSA6Virginia Beach–Chesapeake–Norfolk, VA-NC MSA7Providence–Warwick, RI-MA MSA8Richmond, VA MSA9Hartford–West Hartford–East Hartford, CT MSA10Bridgeport–Stamford–Danbury, CT MSA11New Haven, CT MSA12Worcester, MA MSA13Allentown–Bethlehem–Easton, PA-NJ MSA14Kiryas Joel–Poughkeepsie–Newburgh, NY MSA15Portland–South Portland, ME MSA16Springfield, MA MSA17Waterbury–Shelton, CT MSA18Reading, PA MSA19Manchester–Nashua, NH MSA20Trenton–Princeton, NJ MSA21Hagerstown–Martinsburg, MD-WV MSA22Norwich–New London–Willimantic, CT MSA23Atlantic City–Hammonton, NJ MSA24Barnstable Town, MA MSA25Kingston, NY MSA26Amherst Town–Northampton, MA MSA27Chambersburg, PA MSA28Vineland, NJ MSA29Lexington Park, MD MSA +Largest cities in the Northeast megalopolis with populations over 100,0002020rankCity/TownRegion2020census2010censusChangeLand area2020population density1New York City2Philadelphia3Washington4Boston5Baltimore6Virginia Beach7Newark8Jersey City9Chesapeake10Arlington11Norfolk12Richmond13Yonkers14Worcester15Providence16Newport News17Paterson18Alexandria19Springfield20Bridgeport21Elizabeth22Hampton23Stamford24Lakewood25New Haven26Allentown27Hartford28Cambridge29Smithtown30Manchester31Lowell32Waterbury33Edison34Brockton35Columbia36Woodbridge37Quincy38Lynn39New Bedford

Economy The total GDP of the Northeast megalopolis is $5.6 trillion, of which around $2.3 trillion is from the New York metropolitan area. As of 2023, the Northeast megalopolis would have the third-highest GDP of any nation if it was its own country, ahead of Germany ($4.7 trillion).

+Largest metropolitan statistical areas (MSAs) by GDP within the Northeast Megalopolis2023RankMetropolitan statistical area(MSA)GDP(billions US$)1New York–Newark–Jersey City, NY-NJ MSA2,298.8682Washington–Arlington–Alexandria, DC-VA-MD-WV MSA714.6853Boston–Cambridge–Newton, MA-NH MSA610.4864Philadelphia–Camden–Wilmington, PA-NJ-DE-MD MSA557.6015Baltimore–Columbia–Towson, MD MSA259.6906Virginia Beach–Chesapeake–Norfolk, VA-NC MSA127.4597Hartford–West Hartford–East Hartford, CT MSA122.8058Richmond, VA MSA116.960 9Bridgeport–Stamford–Danbury, CT MSA116.03110Providence–Warwick, RI-MA MSA111.84011New Haven, CT MSA65.23212Worcester, MA MSA64.13513Allentown–Bethlehem–Easton, PA-NJ MSA59.89114Trenton–Princeton, NJ MSA53.00315Portland–South Portland, ME MSA48.03716Harrisburg–Carlisle, PA MSA47.81517Kiryas Joel–Poughkeepsie–Newburgh, NY MSA44.45718Springfield, MA MSA42.35619Manchester–Nashua, NH MSA36.59720Reading, PA MSA25.97521Norwich–New London–Willimantic, CT MSA23.91022Atlantic City–Hammonton, NJ MSA18.72723Barnstable Town, MA MSA18.18724Hagerstown–Martinsburg, MD-WV MSA15.28625Kingston, NY MSA9.90526Lexington Park, MD MSA 9.88327Amherst Town–Northampton, MA MSA9.76628Vineland, NJ MSA8.20929Chambersburg, PA MSA8.149Northeast megalopolis5,598.130

History

Due to its proximity to Europe, the Eastern coast of the United States was among the first regions of the continent to be widely settled by Europeans. Over time, the cities and towns founded on the East Coast had the advantage of age over most other parts of the U.S. However, it was the Northeast in particular that developed most rapidly, owing to a number of fortuitous circumstances.

While possessing neither particularly rich soil—one exception being New England's Connecticut River Valley—nor exceptional mineral wealth, the region still supports some agriculture and mining. The climate is temperate and not particularly prone to hurricanes or tropical storms, which increase further south. However, the most important factor was the "interpenetration of land and sea," which makes for exceptional harbors, such as those at the Chesapeake Bay, the Port of New York and New Jersey, Narragansett Bay in Providence, Rhode Island, and Boston Harbor. The coastline to the north is rocky and little sheltered, whereas to the south it is smooth and does not feature as many bays or inlets that might function as natural harbors. Also featured are navigable rivers that lead deeper into the heartlands, such as the Hudson, Delaware, and Connecticut rivers, which all support large populations and were necessary to early settlers for development. Therefore, while other parts of the country exceeded the region in raw resource value, they were not as easily accessible, and often, access to them necessarily had to pass through the Northeast first.

Modern history