United States Geography

In 1961, a French geographer published a monumental study of the highly urbanized region located in the northeastern United States. Professor Jean Gottmann spent 20 years researching the area extending from southern New Hampshire and northern Massachusetts to Washington, D.C.. He argued that this was a "very special region," and he named it Megalopolis.

Megalopolis was formed along the northeastern coast of the United States by the gradual coalescence of large, independent metropolitan areas. As the populations of these cities grew, the effects of growth spilled over into the surrounding rings of smaller places. Larger suburbs in these rings made their own contributions to the total urban sprawl. The outer fringes of the resultant metropolitan regions eventually began to merge with each other to form an extensive urbanized region.

The dominant theme of Megalopolis is "urban-ness." In varying degrees, urban services provide for the millions who live in this region, and urban forms are never far away. There are office and apartment buildings, small shops and mammoth shopping centers, factories, refineries, residential areas, gas stations, and hamburger stands by the thousands--interspersed with warehouses to store temporarily the goods brought by ship, rail, and truck--all this along the region's 800-kilometer route.

But Megalopolis also contains many green spaces. Some are parks or other land available for recreation; well over 3 million hectares are devoted to farming.

In spite of the mixed character of Megalopolis, it is its massive urban presence that makes this region so important in the United States. Ten of the country's 46 metropolitan areas exceeding 1 million population in 1990 were located in Megalopolis. The region holds 17 percent of the total U.S. population--in only 1.5 percent of the area of the country.

Average per capita income is high, and a higher than average proportion of its residents work in white-collar and professional occupations. Transportation and communication activities are prominent, partly a result of the region's coastal position. Approximately 40 percent of all commercial international air-passenger departures have Megalopolitan centers as their origin. And almost 30 percent of American export trade passes through its six main ports.


Why has this particular portion of the United States developed as it has? Whenever a geographer is asked such a question, the first aspect of the region considered is usually its location. And, indeed, in the case of Megalopolis, the site and the situation of this vast urban region hold clues to its origins and growth.

Many of the site characteristics are visible in the region's outline. Occupying a coastal position, the eastern margin of Megalopolis is deeply convoluted. Peninsulas jut into the Atlantic Ocean. Islands are scattered along the coast, some large enough to support communities. Bays and river estuaries penetrate the landmass in a kind of mirror image of the land's penetration of the ocean. This interpenetrated coastline brings more land area close to the ocean and, in this way, provides greater opportunity for access to cheap water transportation than would a straighter coast.

Quality harbors must also be present, and Megalopolis straddles some of the best natural harbors in America. The northern half of Megalopolis was covered by ice during the most recent of the continental glaciers. As the ice cover began to melt, large river spillways were formed. The erosive power of the rivers cut deeply into the flat coastal plain. As sea level rose, the lower river valleys were "drowned" to form estuaries, and the ocean margin was shifted toward the land's interior. These glacial river valleys formed some of the harbors that later proved useful in the development of Megalopolis.

The other major contribution of the glacial period is more specific to one or two locations. The large amounts of soil, stone, and other debris scraped up by the expanding glaciers were deposited as moraines when the ice front retreated. One series of ridges was left by retreating glaciers just south of what is now the coast of Connecticut. These moraines developed as an island when the seas rose, and it was widened by deposition from the ocean. The island was not made so wide, however, that it could be called anything except Long Island.

Long Island has enhanced the quality of New York's harbor in two major ways. First, the length of coastline available for port facilities, already significant along the Hudson River, is increased considerably. Second, when an urban area grows around a large, fully developed harbor, the growth creates a demand for more space. Good land to accommodate the New York area's urban growth was restricted to the west of the Hudson River in New Jersey by tidal marshes and the erosion-resistant ridge of the Palisades. To the east of the Hudson lies only a narrow finger of land, Manhattan Island. But beyond the East River is Long Island, a flat to slightly rolling land without the barrier marshes of New Jersey. New York's boroughs of Brooklyn and Queens developed early at the western tip of Long Island, and the island offered a great deal of room for further urban expansion toward the east.

Although Megalopolis possesses many high-quality harbors, there are few other site characteristics that contributed so positively to the region's urban economic development. The climate is not exceptionally mild, although the summers are generally of sufficient length and wetness to support farming. Soils are variable, with the soils inland from Baltimore, Maryland, and Philadelphia, Pennsylvania, better than most found closer to New York.

The general topographic features of Megalopolis south of New York do provide additional urban site benefits. Traveling inland from the Atlantic Coast, a very flat coastal plain is succeeded by a rolling, frequently hilly landscape called the Piedmont. The irregularly rolling relief of the Piedmont is underlain by very old, very hard rocks. This surface is resistant to erosion, and the level of the Piedmont is maintained above that of the coastal plain. Wherever rivers flow off the Piedmont, therefore, a series of rapids and small waterfalls are formed along a line tracing the physiographic boundary--a boundary known as the fall line.

Early settlers found the fall line to be a hindrance to water navigation but an obvious source of water power. Settlements developed along the fall line, locations as far inland as possible but still possessing access to ocean shipping. In addition, because the fall line was often the head of navigation, goods brought inland or those to be exported had to be unloaded at fall line locations for transfer to another mode of transport. These sites also benefited from goods moving for export from the interior to the head of river navigation. In many cases, manufacturing processes could be applied here as well.

This portion of North America was also on or near the most direct sea route between Europe and the productive plantations of the Caribbean colonies and southern America, at least on the homeward voyage. The ports around which Megalopolis later grew, therefore, were convenient stopping places and contributed actively to the transoceanic trade that expanded rapidly during the 18th and 19th centuries.

Also critical to this growth was the location of the core cities relative to the country's interior. Philadelphia and Baltimore grew rapidly because each was the focus of a relatively good-sized and good-quality agricultural region. Access routes to the interior were constructed early and helped support the growth of the trading functions of these cities. Inland from Boston, the soils were (and are) too shallow and rocky and the terrain too rolling for good farming, but the New England hills were covered with hardwood and pine forests nearly ideal for ship construction. Also accessible were the very productive fishing banks off the New England coast and farther south in the rich Chesapeake Bay area.

The importance of accessibility in evaluating a city's situation, however, is most apparent in the case of New York, whose chief advantage lay in its position at the head of the best natural route through the Appalachian Mountains. The Hudson-Mohawk River system, later amplified by the Erie Canal, railroads, and highways, provides access to the Great Lakes to the west, which, in turn, provide access to the broad interior of the country. As settlement density and economic activity on the interior plains increased, large amounts of the goods produced were carried to the urban cores of Megalopolis. The city that benefited most from this growing trade was the one with the greatest natural access to the interior: New York.

During America's colonial period, as trade grew between Europe, the Caribbean area, and the American mainland, small-scale manufacturing began to appear in the larger port cities from Baltimore northward. As urban industry grew, the demand for labor increased, drawing immigrants from northwestern Europe or diverting large numbers of workers from farming, thus swelling the populations of these cities. Banks and other financial institutions underwrote investments in local manufacturing and shipping. Service activities, wholesale and retail businesses, centers of information and control all grew and supported further urban expansion, with the greatest growth occurring in New York, Philadelphia, Boston, and Baltimore.

The most unusual feature of this region is not the fact that these cities grew, but that four such large cities (later to become five with the addition of Washington) continued to grow in close proximity to one another. Washington is unique, of course, because even though it, too, is located on the fall line, its growth has followed directly from expansion of the national government structure. The other four cities, along with many smaller ones along the Megalopolitan axis, depended largely on economic stimulation. So great was national growth during the 19th century, and so strong were the linkages between the interior and these four ports, that none of the four could wholly absorb the flow of goods to any of its neighbors and competitors. By the turn of the 20th century, the combined economic resources of these cities' hinterlands had reached continental proportions.


Throughout Megalopolis, it is the urban forms and urban functions that provide the most significant regional unity to the territory. Tall buildings, busy streets, crowded housing, and industrial plants accompany an array of cultural opportunities--theaters, symphony orchestras, art museums, and large libraries. Also sometimes apparent are deterioration--dilapidated structures, traffic congestion, and air pollution. All of these and more are present in the metropolitan areas of Megalopolis.

These characteristics are also found in most large cities around the world. What distinguishes Megalopolis is that the urban characteristics in this region have spread out so far from their core cities that these urban regions have begun to merge with one another in a process of metropolitan coalescence. Megalopolis became in this way a kind of gigantic laboratory in which intensively urban patterns and peculiarly urban problems could be observed developing at a very large scale.

Population densities in Megalopolis are high, averaging about 305 persons per square kilometer in 1987. Of course, some peripheral counties have populations that are only 10 to 20 percent of the region's overall average density. Settlement density increases as a city is approached, until very high densities are reached near the city core. In New York City, for example, 1987 densities exceeded an average of 226 persons per square hectare, which amounts to more than 22,660 persons per square kilometer.

What other features of city organization are associated with this density pattern? Modern cities result basically from the locational consequences of economic activities. When someone decides to move or to relocate a business into a city, the economic advantages of such a choice fundamentally dominate the decision. So pervasive are these advantages that large numbers of people live close to one another, often closer than they would prefer, and tolerate many negative consequences to participate in the benefits of city organization.

An increasing number of urbanites, however, have minimized some disadvantages of city living by moving their residences to suburban locations. Others have moved even farther, into a zone referred to as exurbia. From small towns, areas of converted vacation homes, and rural estates, exurban commuters travel to distant workplaces. But this spread of population has not eliminated the disadvantages of clustering, only shifted the population facing them. It has also spread the workplaces for those living in the region; a smaller proportion of a sprawling metropolitan population than previously still finds it necessary to enter the central city for work.

A key component of the urban landscape is interaction. In general, the cost of moving something is directly proportional to the distance it must be moved. Activities therefore cluster in cities so that movement costs are minimized. The importance of the ability to move from one place to another in urban regions is evident from the high proportion of urban land devoted to facilitating interaction. The lines of interaction for human movement are visible in streets, subways, bridges, tunnels, sidewalks, and parking lots. In older cities such as those in Megalopolis, the downtowns were laid out when travel was by foot and horse-drawn carriage; therefore, these cities have only about 35 percent of their total central areas devoted to landscape features that support human interaction. In newer cities, developed largely after the rise of the automobile, the proportion is much higher.

Other forms of interaction may be equally important but less visible. The easy movement of information and ideas is supported in cities by the intensively developed telephone, telegraph, teletype, and other communications systems. Ninety years ago, the central business districts of all large cities were crowded with spiderweb networks of telephone lines, testifying to the intensity of communication demands; today, telephone lines are wound into cables and placed underground.

Perhaps the prime motivation for interaction is the geographic separation of supply and demand. Economically, if an item or service is needed at a location that cannot meet that need, the good or service must be obtained at another location. Interaction may occur as a result.

The implications of all this for city landscapes should be clear. There are a great many different kinds of activities in a relatively small area. Some functions tend to cluster together, while others are scattered across the urban region. Since a variety of activities are carried on in a city, interaction is stimulated between functions or within zones of the same function. When the activities are mapped, the result is a greatly mixed pattern of land use.

The concentration of population and urban activities requires supporting functions as well. Traditionally organized and operated as various branches of city government, these public service functions are only indirectly productive in an economic sense, but they are necessary for commerce and industry.

In addition to such services as water, electricity, and sewage and garbage collection, cities provide police and fire protection, construction and maintenance of public movement facilities, health care, documentation of vital population statistics, and educational facilities, among others.

So pervasive did these services become in large cities that immense governmental structures developed to administer them. In the New York metropolitan region, to take the extreme case, more than 1,550 administrative agencies were in operation in 1982.

Yet another major component of the urban landscape is its level of accessibility. Easy access between most sections of an urban area has not always been a dominant consideration in city organization and structure. The original street plans of most cities in Megalopolis, for example, followed the simple square or rectangular grid pattern popular in the 17th and 18th centuries.

As these cities grew, the inadequate access provided by this street system became apparent. A square grid, for example, possesses frequent, right-angle intersections. Because the traffic flow is interrupted at each intersection, a greater traffic volume leads to longer pauses at each intersection. By 1900, Baltimore and Boston had each exceeded populations of 500,000, Philadelphia had reached nearly 1.3 million, and New York was approaching 3.5 million. The main impact of the automobile was then still in the future, but serious congestion was already present in these cities' centers.

Beginning in the 1950s, changes occurred that led to the rapid areal expansion of cities and the increased use of automobiles for travel. An increasing proportion of the work force in the cities began to live at distances and in residential densities that made it uneconomical for mass transit to reach them. Economically, the speed and flexibility of truck transport accelerated the diversion of short-haul freight from rail to road carriers. Traffic planners responded by recommending construction of peripheral circumferential, or ring, highways and high-volume, limited-access expressways to separate local movement from cross-town and through traffic. Partly successful, these changes, plus others, also increased demand for access within the city center, between the center and the periphery, and eventually between sections of the periphery. The entire pattern of accessibility became more complex and difficult to manage.

All of this accentuates another component of the urban landscape. This is a landscape of change. Tens of thousands of new residents enter a large city like Philadelphia or New York each year. Even greater numbers have been leaving, some to distant cities and some only into the metropolitan fringes. Structures are destroyed, new ones built. Street patterns are altered, the pattern of functions is changed, and flows of people, goods, and ideas are shifted to fit these new patterns.

Such changes may be observed in any major region in America, but, in some ways, they actually created Megalopolis.


Perhaps the most fundamental and far-reaching change in Megalopolis during the last 40 years has been the great areal expansion of major metropolitan areas. Greater New York clearly has extended its population the farthest, but the Boston, Philadelphia, Baltimore, and Washington areas have also grown greatly. New York had both the largest initial population and the most intensive economic concentration, but the other three port cities possessed firm foundations for growth as well. At the same time, the federal government rapidly expanded its operations. The District of Columbia (Washington and the District of Columbia are coextensive) was no longer large enough to absorb the burgeoning civil service population and the growing number of people needed to feed, clothe, and otherwise serve them. Urban development spilled into the neighboring states of Virginia and Maryland.

The spread of urban population far beyond city limits also had a strong impact on rural activities in Megalopolis. As city populations grew, a greater number of people had to be fed by foodstuffs shipped in from rural areas. The tens of millions of people in urban Megalopolis consume agricultural products from across America and beyond. Many of those farming the agricultural land close to the cities, however, chose to specialize in higher-priced foods and in products with high perishability. Dairy products, tomatoes, lettuce, apples, and a variety of other intensively produced "table crops" came to dominate farm production in sections of rural Megalopolis.

Also, as land on the margins of urban areas was approached by dense settlement and intense economic activity, the price of land was driven up. A 60-hectare farm purchased decades ago for $20,000 as agricultural land might eventually be sold to a real estate developer for $1 million. The developer, in turn, might subdivide the land into 250 home lots of 0.2 hectares each and then, after putting in utilities and streets, sell each lot for $25,000, or a total $6.25 million.

Even if a farm family could resist the profitability of such a sale, the taxes on the land rose sharply toward urban levels as nearby areas begin to be used for urban activities. Until land use controls were put in place to keep land in agriculture, the only way for a family to remain in farming was to pursue intensive agricultural production devoted to high-value products.

Urban sprawl and the corresponding shifts in agricultural practices in Megalopolis were pulled along the main lines of interurban access between the major urban nodes. Strong flows of traffic developed early between the cities of Megalopolis. When people who continued to work within the major cities relocated their residences, it was only natural that a high proportion chose sites that allowed them easy access to the main cluster of workplaces. The arterial highways and, to a lesser extent, the interurban railroads and main feeder roads became the seams along which metropolitan populations spread first and farthest. As a consequence, the urbanized areas merged first along these main interurban connections. And the demand for increased accessibility generated the construction of even better interurban movement facilities.

As the populations of the separate urban areas grew, the composition of the populations also changed. Prior to 1910, the cities of Megalopolis absorbed large numbers of immigrants from Europe. These migrants passed through one or another of the large Megalopolitan ports, usually New York. Those who did not continue westward into the farming areas or urban centers of the Midwest and Great Plains settled in dense clusters within Megalopolis's cities, usually forming communities of each nationality.

When World War I broke out in Europe, the flow of emigrants stopped, and a new set of migration flows began to filter into Megalopolis. What had been a slow trickle of black migration from southern states began to grow. Black migrants and groups of rural whites from the region repeated the patterns of settlement used by migrant groups from Europe. Most blacks settled within the cities in areas that were already occupied by small black populations.

As the black migration continued through mid-century, population densities increased and generated outward expansion from the original core areas. Often, after many decades of population increase within a city, black densities began to increase in outlying regions of black settlement as well.

Two entirely new aspects of urban change appeared during recent years--a change that may be national in scope but is most dramatic in the largest and oldest cities such as Megalopolis's ports.

First, during the late 1960s, for the first time in U.S. history, people began to leave the largest metropolitan regions--considering both central city and suburbs together--in greater numbers than those who moved in. Smaller cities and towns and the rural areas between them in general have been the primary recipients of these population shifts.

Second, there has been an eruption of high-rise office clusters at various locations in metropolitan areas. The appearance of new metal and glass office skyscrapers has transformed the downtown skyline of many American cities since the mid-1970s. But this feature is no longer limited to the old city cores. Massive office clusters have emerged within the suburban rings surrounding the central cities--many exceeding the square footage of office space of a major city downtown. This change is one that appears to affect most significantly the location of jobs and the pattern of travel to them, rather than the location of residences.

Clearly, urban areas are landscapes of change, and the changes in Megalopolis suit the unusual character of the region. The changes there have been continuous, they have been drastic, and they have occurred on a scale unmatched anywhere else in the world.

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Source: U.S. Department of State