ABSTRACT
This chapter begins with the United States Department of Agriculture (USDA) "rural-urban continuum" and "urban influence" constructs. It explains the construct of a rural-megapolitan continuum. In particular, the three metropolitan size categories used in the USDA rural-urban continuum are combined with the micropolitan areas adjacent to metropolitan areas, other noncore counties also adajcent to metropolitan areas, and all others. The USDA has developed a set of Rural-Urban Continuum Codes that allows analysts to distinguish among metropolitan counties by the population size of their metropolitan area, and nonmetropolitan counties by their degree of urbanization and proximity to a metropolitan area. Within three the urban categories, nonmetropolitan counties are sorted by whether they have some functional adjacency to a metropolitan area or areas, as determined by the USDA. A variant of the rural-urban continuum developed by the USDA is the urban influence construct. The USDA's 2003 Urban Influence Codes assigns 3,141 counties, county equivalents, and independent cities to 12 groups.
