Adulthood is both a demographic marker and an extended developmental phase. The U.S. legal system and many health researchers recognize adulthood as ages 18 to 64, when adults are considered "older" adults. However, the descriptor "rural" is much more open to interpretation. Even the federal government does not agree on the definition – Commerce, Education, Health and Human Services, and other Departments each define "rurality" differently based on factors such as proximity to a metropolitan area, population density, and culture or even personality.

Recently, the U.S. Office of Management and Budget (OMB), the Economic Research Service of the U.S. Department of Agriculture (USDA), and the Census Bureau have proposed a nine-point continuum for classifying counties by degree of rurality. This continuum is increasingly being used by a cross-section of researchers, many of whose work forms the basis of this module.

View full report from United States Department of Agriculture - Economic Research Service