Another way to look at population and development trends is to focus on land development patterns and how they have changed over time, the principal concern of this study. According to the U.S. Department of Agriculture’s National Resources Inventory (NRI),2 between 1982 and 2003, an estimated 35 million acres of land (55,000 square miles) was developed in the United States—approximately one-third of all the land that had been developed by 2003.3 In all, 108.1 million acres was classified as developed in 2003—approximately 5.6 percent of the national total. Developed land grew at almost twice the rate of population over this 21-year period, clearly indicating that population densities were declining.4

Population and land development patterns, however, exhibit considerable variation across the United States. For example, some rapidly growing western states, such as California, Nevada, and Arizona, added population to their metropolitan statistical areas (MSAs) at a faster rate than they were spreading out (Fulton et al. 2001).5 At the same time, slowly growing MSAs of the northeast and midwest expanded in land area even as their population growth slowed or reversed. Overall, the northeast and midwest regions each gained about 7 percent in population, but their urbanized land increased by 39 and 32 percent,


The NRI is a national longitudinal panel survey based on a sample of nonfederal land in all 50 states and Puerto Rico. Periodic inventories are conducted to estimate changes in the amount of developed land, among other objectives. Consistent data for this purpose are available going back to 1982.


According to the NRI, developed land covers a combination of land use categories, including urban and built-up areas and rural transportation land (NRCS 2002).


Developed land grew from 72.9 million acres in 1982 to 108.1 million acres in 2003, a 48 percent increase (NRCS 2007, 5), while the U.S. resident population increased from 232.2 million in 1982 to 290.9 million in 2003, nearly a 25 percent increase (U.S. Bureau of the Census 2008, 7).


Land use trends examined by Fulton et al. are focused on the “urban and built-up” category of developed land as defined by the NRI, which the authors define as urbanized land. Population data are focused on MSAs, a U.S. census designation. An MSA is defined as a core-based statistical area associated with at least one urbanized area that has a population of at least 50,000. The MSA comprises the central county or counties containing the core, plus adjacent outlying counties having a high degree of social and economic integration with the central county as measured through commuting (OMB 2000).

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