In any landscape one would expect to find a number of cities of the same or similar importance, and the areas in between these cities are often served by more than one city. In other words, the areas of influence of neighbouring cities tend to overlap, thus generating a zone of competition in between. Whichever city exercises a dominant influence- its influence in that zone of competition is greater than the influence of any other city. The area of dominance of a city is an exclusive area and is, therefore, of great significance in terms of territorial or regional divisions. Further, the dominant area in reality is dominant not only with respect to one or two services, but with respect to all services of equal importance. Thus, the area of dominance is a multifunctional area, while
the area of influence is essentially a uni-functional area.

The areas of city influence and dominance are further complicated by existence of a hierarchy of cities and urban places which give rise to sets of areas of influence and dominance, one within the other. The city region may be defined as the area of dominance of a city corresponding to its hierarchical level. However, the same city also performs functions of a lower hierarchical order. As a result, each city may have more than one area of dominance. In fact, several areas of dominance fall within the city region in a concentric form. Similarly, for each hierarchical level we have a set of areas of influence representing each service or function. The city region is the largest of the several areas of dominance around a city.