American cities, more so than the small-town or agrarian landscape, tend to be the product of a particular period rather than of location. The relatively venerable centers of the Eastern Seaboard—Boston; Philadelphia; Baltimore; Albany, New York; Chester, Pennsylvania; Alexandria, Virginia; or Georgetown (a district of Washington, D.C.), for example—are virtual replicas of the fashionable European models of their early period rather than the fruition of a regional culture, unlike New Orleans and Santa Fe, New Mexico, which reflect other times and regions. The townscapes of Pittsburgh; Detroit, Michigan; Chicago; and Denver, depict national modes of thought and the technological development of their formative years, just as Dallas, Texas; Las Vegas, Nevada; San Diego; Tucson, Arizona; and Albuquerque, New Mexico, proclaim contemporary values and gadgetry more than any local distinctiveness. When strong-minded city founders instituted a highly individual plan and their successors managed to preserve it—as, for example, in Savannah, Georgia; Washington, D.C.; and Salt Lake City, Utah—or when there is a happy combination of a spectacular site and appreciative residents—as in San Francisco or Seattle—a genuine individuality does seem to emerge. Such an identity also may develop where immigration has been highly selective, as in such places as Miami, Florida; Phoenix, Arizona; and Los Angeles.

As a group, U.S. cities differ from cities in other countries in both type and degree. The national political structure, the social inclinations of the people, and the strong outward surge of urban development have led to the political fragmentation of metropolises that socially and economically are relatively cohesive units. The fact that a single metropolitan area may sprawl across numerous incorporated towns and cities, several townships, and two or more counties and states has a major impact upon both its appearance and the way it functions. Not the least of these effects is a dearth of overall physical and social planning (or its ineffectuality when attempted), and the rather chaotic, inharmonious appearance of both inner-city and peripheral zones painfully reflects the absence of any effective collective action concerning such matters.

The American city is a place of sharp transitions. Construction, demolition, and reconstruction go on almost ceaselessly, though increasing thought has been given to preserving monuments and buildings. From present evidence, it would be impossible to guess that New York City and Albany date from the 1620s or that Detroit was founded in 1701. Preservation and restoration do occur, but often only when it makes sense in terms of tourist revenue. Physical and social blight has reached epidemic proportions in the slum areas of the inner city; but, despite the wholesale razing of such areas and the subsequent urban-renewal projects (sometimes as apartment or commercial developments for the affluent), the belief has become widespread that the ills of the U.S. city are incurable, especially with the increasing flight of capital, tax revenue, and the more highly educated, affluent elements of the population to suburban areas and the spatial and political polarization of whites and nonwhites.

In the central sections of U.S. cities, there is little sense of history or continuity; instead, one finds evidence of the dominance of the engineering mentality and of the credo that the business of the city is business. Commercial and administrative activities are paramount, and usually there is little room for church buildings or for parks or other nonprofit enterprises. The role of the cathedral, so central in the medieval European city, is filled by a U.S. invention serving both utilitarian and symbolic purposes, the skyscraper. Some cities have felt the need for other bold secular monuments; hence the Gateway Arch looming over St. Louis, Seattle’s Space Needle, and Houston’s Astrodome. Future archaeologists may well conclude from their excavations that American society was ruled by an oligarchy of highway engineers, architects, and bulldozer operators. The great expressways converging upon, or looping, the downtown area and the huge amount of space devoted to parking lots and garages are even more impressive than the massive surgery executed upon U.S. cities a century ago to hack out room for railroad terminals and marshaling yards.

Within many urban sites there has been radical physical transformation of shoreline, drainage systems, and land surface that would be difficult to match elsewhere in the world. Thus, in their physical lineaments, Manhattan and inner Boston bear scant resemblance to the landscapes seen by their initial settlers. The surface of downtown Chicago has been raised several feet above its former swamp level, the city’s lakefront extensively reshaped, and the flow of the Chicago River reversed. Los Angeles, notorious for its disregard of the environment, has its concrete arroyo bottoms, terraced hillsides and landslides, and its own artificial microclimate.

The supercities

The unprecedented outward sprawl of American urban settlement has created some novel settlement forms, for the quantitative change has been so great as to induce qualitative transformation. The conurbation—a territorial coalescence of two or more sizable cities whose peripheral zones have grown together—may have first appeared in early 19th-century Europe. There are major examples in Great Britain, the Low Countries, and Germany, as well as in Japan.

Nothing elsewhere, however, rivals in size and complexity the aptly named megalopolis, that supercity stretching along the Atlantic from Portland, Maine, past Richmond, Virginia. Other large conurbations include, in the Great Lakes region, one centered on Chicago and containing large slices of Illinois, Wisconsin, and Indiana; another based in Detroit, embracing large parts of Michigan and Ohio and reaching into Canada; and a third stretching from Buffalo through Cleveland and back to Pittsburgh. All three are reaching toward one another and may form another megalopolis that, in turn, may soon be grafted onto the seaboard megalopolis by a corridor through central New York state.

Another example of a growing megalopolis is the huge southern California conurbation reaching from Santa Barbara, through a dominating Los Angeles, to the Mexican border. The solid strip of urban territory that lines the eastern shore of Puget Sound is a smaller counterpart. Quite exceptional in form is the slender linear multicity occupying Florida’s Atlantic coastline, from Jacksonville to Miami, and the loose swarm of medium-sized cities clustering along the Southern Piedmont, from south-central Virginia to Birmingham, Alabama; also of note are the Texas cities of Dallas–Fort Worth, Houston, and San Antonio, which have formed a rapidly growing—though discontinuous—urbanized triangle.

One of the few predictions that seem safe in so dynamic and innovative a land as the United States is that, unless severe and painful controls are placed on land use, the shape of the urban environment will be increasingly megalopolitan: a small set of great constellations of polycentric urban zones, each complexly interlocked socially and physically with its neighbors.