Urban Hierarchy

Urban areas exhibit a large range of population sizes—from hamlets to global cities—each having a corresponding economic role within the urban system. Settlements with larger populations that provide more and diverse services are higher up the urban hierarchy. Settlements with smaller populations and a limited number and type of services are further down the urban hierarchy. The size and distribution of urban areas within this system have important implications for economic development.

The urban hierarchy may be illustrated by a pyramid where the smallest settlements (hamlets) are at the bottom of the pyramid and global cities are at the top (Figure 1). Settlements at the bottom of the pyramid have small, rural populations and [Page 2950]contain a small number and limited variety of economic services within the system. This type of settlement is the most dominant and widespread. Settlements at the top of the pyramid have large, urban populations and contain a large number and wide array of economic services. Usually, there is one settlement at the top of the urban system. As you move up the urban hierarchy, the number of settlements in each category declines as the populations and the number and diversity of services expand. For example, in the United States, the city at the top of the urban hierarchy is New York, which has the country's largest population; is a major global financial, transportation, and cultural center; and offers a wide variety of social and economic services. Just below this level would be cities such as Los Angeles and Chicago, both of which have large, urban populations and offer numerous retail, financial, medical, education, and cultural services. One step below on the urban hierarchy, we will find cities such as Atlanta, Denver, Seattle, and Miami. Each has large urban populations, but they are smaller in size than the populations of New York City, Chicago, and Los Angeles. They also offer a somewhat smaller number of services. Below this level, we find cities that might be the largest cities within a state and/or state capitals. These cities serve an important economic and administrative role at a statewide or perhaps regional level. Smaller cities that are not state capitals or are not the largest cities within a state are found at the next level. They supply services to a portion or region of the state and have a significantly smaller population. Towns with smaller populations and a smaller array of services depend on nearby cities for more diverse services. Hamlets have small populations and very limited services, such as gas stations, convenience and/or grocery stores, and restaurants.

Figure 1 Population, settlements, and services in the urban hierarchy

Source: Author.

Figure 2 Urban hierarchy and economic development

Source: Author.

In the early stages of development and in agriculturally based economic systems, settlements typically are of similar size and are evenly distributed across the landscape (Figure 2, Stage 1). This pattern minimizes transportation costs and competition. Over time, one city or settlement (the core) gains dominance or power over other settlements in the system (Figure 2, Stage 2). This core or primate city may be centrally located compared with the other cities, or it may have an ideal location as a port city for access to water transportation. Primate cities are the largest and most dominant cities within a system of cities. Primate cities have populations many times greater than the second largest and subsequent cities. Usually, primate cities were once centers of much larger systems (e.g., empires). Over time, city systems tend to move toward a rank size distribution (Figure 2, Stage 3).

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