In 1950, only 20 percent of Americans lived in suburbs
compared to 40 percent in cities and 40 percent in small
towns and rural areas. In 2000, after a half-century of rapid
suburban growth, 50 percent of Americans lived in suburbs compared to only 30 percent in cities and 20 percent
in small towns and rural areas. ■
Urban Expansion
Until recently in the United States, as cities grew, they expanded
by adding peripheral land. Now cities are surrounded by a
collection of suburban jurisdictions whose residents prefer to
remain legally independent of the large city.
Annexation
The process of legally adding land area to a city is annexation.
Rules concerning annexation vary among states. Normally,
land can be annexed to a city only if a majority of residents in
the affected area vote in favor of doing so.
Peripheral residents generally desired annexation in the
nineteenth century, because the city offered better services,
such as water supply, sewage disposal, trash pickup, paved
streets, public transportation, and police and fire protection.
Thus, as U.S. cities grew rapidly in the nineteenth century, the
legal boundaries frequently changed to accommodate newly
developed areas. For example, the city of Chicago expanded
from 26 square kilometers (10 square miles) in 1837 to 492
square kilometers (190 square miles) in 1900 (Figure 13-19).
Today, however, cities are less likely to annex peripheral land
because the residents prefer to organize their own services rather
than pay city taxes for them. Originally, some of these peripheral
jurisdictions were small, isolated towns that had a tradition of
independent local government before being swallowed up by
urban growth. Others are newly created communities whose residents wish to live close to the large city but not be legally part of it.
Defining Urban Settlements
Instead of annexing peripheral areas, cities now are surrounded
by suburbs. As a result, several definitions have been created to
characterize cities and their suburbs:
• City: a legal entity
• Urbanized area: a continuously built-up area
• Metropolitan area: a functional area
THE CITY. The term city defines an urban settlement that has
been legally incorporated into an independent, self-governing
unit (Figure 13-20). In the United States, a city surrounded by
suburbs is sometimes called a central city.
Virtually all countries have a local government system that
recognizes cities as legal entities with fixed boundaries. A city
has locally elected officials, the ability to raise taxes, and responsibility for providing essential services. The boundaries of the
city define the geographic area within which the local government has legal authority.
Population has declined since 1950 by about one-half in the
central cities of Baltimore, Buffalo, Cleveland, Detroit, Pittsburgh,
and St. Louis, and by about one-third in Birmingham, Boston,
Cincinnati, Dayton, Newark, Rochester, and Syracuse. The number of tax-paying middle-class families and industries has invariably declined by much higher percentages in these cities.
URBANIZED AREA. In the United States, the central city
and the surrounding built-up suburbs are called an urbanized
area. More precisely, an urbanized area consists of a central city
1870 1900
1890 1930
City limits
in 1837
Annexed by
1960
1990
Lake
Michigan
Lake
Calumet
O'Hare
Field
290
294
90
94
57
90
55
94
0
0 2.5 5 KILOMETERS
2.5 5 MILES
Chicago
MSA
0 50 KM
FIGURE 13-19 Annexation in Chicago. During the nineteenth century, the
city of Chicago grew rapidly through annexation of peripheral land. Relatively
little land was annexed during the twentieth century; the major annexation was
on the northwest side for O’Hare Airport. The inset shows that the city of
Chicago covers only a small portion of the Chicago metropolitan statistical area.
Chapter 13: Urban Patterns 425
watch the city’s television stations, read the city’s
newspapers, and support the city’s sports teams.
Therefore, we need another definition of urban
settlement to account for its more extensive
zone of influence.
The U.S. Bureau of the Census has created a
method of measuring the functional area of a
city, known as the metropolitan statistical area
(MSA). An MSA includes the following:
• An urbanized area with a population of at
least 50,000
• The county within which the city is located
• Adjacent counties with a high population
density and a large percentage of residents
working in the central city’s county (e.g., a
county with a density of 25 persons per
square mile and at least 50 percent working in
the central city’s county)
Studies of metropolitan areas in the United
States are usually based on information about
MSAs. The MSAs are widely used because many
statistics are published for counties, the basic
MSA building block.
