URBANIZATION IS THE process by which large numbers of people become permanently concentrated in relatively small areas, forming cities. The definition of what constitutes a city changes from time to time and place to place, but it is most usual to explain the term as a matter of demographics. The United Nations has recommended that countries regard all places with more than 20,000 inhabitants living close together as urban; but, in fact, nations compile their statistics on the basis of many different standards. For instance, the UNITED STATES uses “urban place” to mean any locality where more than 2,500 people live.

Large permanent assemblies of people have arisen historically in two sharply contrasting ways. Some settlements emerge because a group of people chose to live near each other in order to realize a way life made possible by production activities carried on elsewhere. Other settlements arise because people who work within certain production facilities wish to live in the immediate vicinity of these facilities. In general, then, population may be permanently assembled in order to consume the products and services of labor, regardless of where they are produced, or in order to produce products and services, regardless of where they are consumed.