The quest to define what constitutes "rural" in the United States is far from straightforward. Researchers and policymakers often find themselves grappling with multiple definitions, each with its own set of criteria and geographic building blocks. This multiplicity of rural definitions reflects the complex reality that rural and urban areas can be distinguished using various geographic concepts and population thresholds.
The U.S. Census Bureau provides an official, statistical definition of rural based strictly on housing unit and population density measures. According to the Bureau's current delineation, released in 2022 and based on the 2020 decennial census, rural areas comprise open country and settlements with fewer than 2,000 housing units and 5,000 residents. Conversely, urban areas consist of densely developed regions with 2,000 or more housing units or 5,000 or more residents. Notably, urban areas do not necessarily adhere to municipal boundaries; they are essentially densely settled territories as they might appear from an aerial perspective.
In contrast, the Office of Management and Budget (OMB) employs a different approach to distinguish rural from urban areas. The OMB defines metropolitan (metro) areas as broad labor-market areas that include central counties with one or more urban areas of 50,000 or more people, as well as outlying counties economically tied to the central counties through labor-force commuting patterns. Nonmetropolitan (nonmetro) counties, often used to depict rural and small-town trends, fall outside the boundaries of these metro areas.
The choice between these two definitions can have significant implications for who and what is considered rural. In 2020, 46 million people resided in OMB-defined nonmetro counties, accounting for 13.8% of the U.S. population. In contrast, Census-defined rural areas included 66.3 million residents, or 20% of the population. These two classifications identify very different sets of people, with the majority of rural residents (56%) living in metro counties, while 36% of nonmetro residents reside in urban areas.
The Census Bureau's criteria for defining urban areas have undergone significant changes in recent years. In 2020, housing unit density replaced population density as the primary measure for designating census blocks as urban. Additionally, the minimum population size to qualify as an urban area increased from 2,500 to 5,000 people. These modifications have had ripple effects on the delineation of metro and micro areas.
Researchers and policy officials must carefully consider the purpose of their application when selecting a rural definition. For instance, tracking urbanization's influence on farmland prices is best approached using the Census Bureau's urban-rural definition, as it distinguishes built-up territory from surrounding, less developed land. On the other hand, studies designed to track and explain economic and social changes often opt for the OMB's metro-nonmetro classification, as it reflects a regional labor-market concept and allows for the use of widely available county-level data.
Ultimately, the key is to employ a rural-urban definition that best fits the needs of a specific research or policymaking endeavor. It is crucial to recognize that any simple dichotomy obscures a complex rural-urban continuum, often with subtle gradations from one level to the next. By embracing the nuances and complexities inherent in defining rural areas, researchers and policymakers can develop more targeted and effective strategies to address the unique challenges and opportunities faced by these diverse communities.
