How do you define if an area is rural? A paper by Bennett et al. (2019) provides some options.
- Population density. This is one of the simplest approaches and can be applied to any geographic unit. However, it may be problematic for geographic units with a mix of urban and rural sections.
- MSA-based. The Office of Management and Budget (OMB) defines Metropolitan and Micropolitan Statistical Areas at the county level. However, OMB explicitly says that these definitions are not intended to define rurality.
- Urban influence codes. Department of Agriculture’s Economic Research Service has created two additional county schemes. Urban Influence Codes divide counties into groups based on their size and adjacency to other county types. Rural-Urban Continuum Codes provide a designation that is also based upon the OMB county designations. Similar to the Urban Influence Codes, these codes are categorized by population size and adjacency to metropolitan areas
- Frontier and Remote Area Codes. The Economic Research Service has also developed Frontier and Remote Area Codes. These codes are ZIP code based and specific to rural places, unlike many classifications that begin with urban areas and leave rural ones to be defined as a residual. The codes provide four options for categorizing a ZIP code, based on the size of the biggest city or town in that ZIP code and the travel distance to a larger city or town.
- Other definitions. Examples include the Economic Research Service’s natural amenities scale and County Typology Codes; the Department of Veterans Affairs’ rurality definitions and the Index of Relative Rurality
Many of these definitions are based on different geographical units. Some county, some ZIP code, some Census tracts. However, using counties–while useful because easily linkable to many other data sets–is problematic since county size varies tremendously around the country.
County sizes range from just 13.2 square miles to more than 20,000 square miles (and up
to 147,805 square miles if Alaska boroughs are included), while populations range from eighty eight to more than ten million residents…For example, Maine and Indiana are roughly the same in terms of area, but Maine has sixteen counties while Indiana has ninety-two…St. Louis County, Minnesota, is the largest county east of the Mississippi River, stretching from the Canadian border to the southernmost port on Lake Superior. It contains Duluth— Minnesota’s fourth-largest city, with a population of 86,293—making the county metropolitan by the OMB definition. However, it also contains Voyageurs National Park and the million-acre
Boundary Waters Canoe Area Wilderness.