System Dimensions: Extent
Adequate Data Available   Download This Indicator (.pdf)

Note that the data published in the 2002 State of the Nation’s Ecosystems Report as well as the 2003 and 2005 Web-Only Updates have been superseded by the 2008 Report and thus should be used with caution. For the most recent data, purchase the 2008 Report from Island Press.

Graphs of urban and suburban areas by regions
View Data on Urban and Suburban Areas, by Region
View Data on Urban and Suburban Areas As a Portion of Total Land Area
View Data on Composition of Undeveloped Urban/Suburban Lands. 1992

What Is This Indicator, and Why Is It Important? This indicator reports the extent of urban and suburban lands, both in acres and as a percentage of all land area in a region; it also reports on the extent and composition of undeveloped lands, such as wetlands, croplands, forest, or grassland and shrubland, contained within urban and suburban areas.

About 75% of all Americans live on land that is urban or suburban in character, which is less than 2% of the lower 48 states. Increases in urban/suburban area are generally permanent and may affect the use and character of surrounding lands (see the land use change indicator). Describing the amount and composition of undeveloped lands provides a coarse view of how intensely developed urban and suburban lands are, which is related to the amount and type of open space available to a region’s residents (see pubically accessible open space), the extent of impervious surfaces (see total impervious area), and the services provided by the “natural” systems in urban and suburban areas (see natural ecosystem services).

What Do the Data Show? In 1992, urban and suburban areas occupied 32 million acres in the lower 48 states, or 1.7% of total land area. Most of the land designated urban or suburban is in the South and Midwest, but cities and suburbs account for less than 2% of the land area in those regions. In comparison, urban and suburban lands in the Northeast made up over 5% of the landscape.

The South, Northeast, and West had nearly identical percentages of undeveloped land within their urban and suburban areas (about 22%), while the Midwest had less (17%). In the Northeast and South, forests dominate these undeveloped areas; in the Midwest, farmlands dominate, and in the West grasslands and shrublands dominate.

Discussion The definition of urban and suburban areas used here is fairly restrictive. It focuses on highly urbanized areas and their surrounding suburbs, plus developed outlying areas above a minimum size. It covers residential areas, commercial and industrial areas, parks and golf courses, and the like. It is not delineated on the basis of jurisdictional boundaries, but rather on actual land cover as identified using satellite data, and can be applied repeatedly over time. Other programs (see technical note), such as those that tally all developed lands, whether or not they are sufficiently aggregated to be considered “suburban,” identify more developed lands than are reported here.

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