John, Patricia La Caille.
Rural Information Center (U.S.)
What is Rural?
Beltsville, MD : USDA, National Agricultural Library, Rural Information Center, 
Many people have definitions for the term rural, but seldom are these rural definitions in agreement.
For some, rural is a subjective state of mind. For others, rural is an objective quantitative measure. The June 2008 Amber Waves publication from the USDA, Economic Research Service, provides new insight to rural definitions with an article,"Defining the “Rural” in Rural America: The use of different definitions of rural by Federal agencies reflects the multidimensional qualities of rural America." http://www.ers.usda.gov/AmberWaves/June08/Features/RuralAmerica.htm
The General Accounting Office, in its publication Rural Development: Profile of Rural Areas, http://archive.gao.gov/t2pbat6/149199.pdf, pp. 26-31, discusses the three most common Federal definitions of rural: that of the Department of Commerce's Bureau of the Census based on the 1990 census criteria (now superceded by the 2000 census criteria), http://www.census.gov/geo/www/ua/ua_2k.html, that of
the White House's Office of Management and Budget, and that of the Department of Agriculture's Economic Research Service.
"Metro/urban areas can be defined using several criteria. Once this is done,
nonmetro/rural is then defined by exclusion -- any area that is not metro/urban is
nonmetro/rural. Determining the criteria used has a great impact on the resulting
classification of areas as metro/ nonmetro or urban/rural. The Census Bureau classifies
61.7 million (25 percent) of the total population as rural, OMB classifies 55.9 million
(23 percent) of the total population as nonmetro. According to the Census definition, 97.5
percent of the total U.S. land area is rural; according to the OMB definition, 84 percent
of the land area is nonmetropolitan. USDA/ERS estimates that, in 1990, 43 percent of the
rural population lived in metropolitan counties.
A further problem with dichotomous definitions is that they permit classification into only
two categories -- metro/urban or nonmetro/rural. This cannot describe the metro/nonmetro continuum
or the range of variation that exists in nonmetro areas. ERS attempts to overcome this limitation by
further subdividing metro/nommetro categories. ... However, as with any definition, any broad generalizations
about nonmetro conditions will not necessarily be representative for a subset of those areas.
For the purpose of illustration, the primary three definitions are presented here:
The Bureau of the Census
defines an urbanized area, http://www.census.gov/population/censusdata/urdef.txt, (UA) by population density. According
to this definition, each UA includes a central city and the surrounding densely settled
territory that together have a population of 50,000 or more and a population density
generally exceeding 1,000 people per square mile. A "county" is a political
distinction and is not incorporated in the Bureau of the Census' classification scheme, so
one UA may cover parts of several counties.
Under this definition, all persons living in
UA's and in places (cities, towns, villages, etc.) with a population of 2,500 or more
outside of UA's are considered the urban population. All others are considered rural.
an urbanized area (defined by the Bureau of the Census) with at least 50,000 inhabitants
and a total MSA population of at least 100,000 (75,000 in New England).
These standards provide that each MSA must include the county in which the central city
is located (the central county) and additional contiguous counties (fringe counties), if
they are economically and socially integrated with the central county. Any county not
included in an MSA is considered nonmetro.
OMB periodically reclassifies counties on the basis of Census data and population
ERS [USDA] uses
rural-urban continuum codes, http://www.ers.usda.gov/briefing/rurality/RuralUrbCon/, to distinguish metro counties by size and
nonmetro counties by their degree of urbanization or proximity to metro areas. USDA
defines codes zero to 3 as metro, and 4 to 9 as nonmetro."1 [e.g., 4 = Urban
population of 20,000 or more, adjacent to a metro area, and 9 = Completely rural or urban
population of fewer than 2,500, not adjacent to a metro area]"
1Rural Development : Profile of Rural Areas. United States General Accounting
Office. Fact Sheet for Congressional Requestors. GAO/RECD-93-40FS. Washington, DC: The
Office, 1993: pp. 26-29.
Rural/Urban Definitions: Alternatives and Numbers by State. Wanqing Zhang, Angella Bowman, Keith J. Mueller. Project Report 98-1. Omaha, NE: Nebraska Center for Rural Health Research, University of Nebraska Medical Center, 1998. 13 p. http://www.unmc.edu/rural/documents/pr9801.pdf
Improving the Operational Definition of "Rural Areas" for Federal Programs. Harold F. Goldsmith, Dena S. Puskin, Dianne J. Stiles. Rockville, MD: U.S. Department of Health and Human Services, Health Resource and Services Administration, Office of Rural Health Policy, 1993. 11 p. http://www.ruralhealth.hrsa.gov/pub/Goldsmith.htm
Low Density Counties with Different Types of Sociodemographic, Economic and Health/Mental Health Characteristics, Letter to the Field No. 18. Harold F. Goldsmith, and others. Boulder, CO: Frontier Mental Health Services Resource Network, 2000? 18 p. http://www.wiche.edu/MentalHealth/Frontier/letter18.html
Rural Populations and Health Care Providers: A Map Book. Randy K. Randolph, Katherine Gaul, Rebecca T. Slifkin. Chapel Hill: North Carolina Rural Health Research and Policy Analysis Center, Cecil G. Sheps Center for Health Services Research, University of North Carolina, 2002. 1 v. (various pagings) http://www.shepscenter.unc.edu/research_programs/rural_program/mapbook2003/
Shortage Designation. Rockville, MD: U.S. Department of Health and Human Services, Health Resources and Services Administration. http://bhpr.hrsa.gov/shortage/
Rural America At a Glance. Karen Hamrick, editor. Rural Development Research Report No. (RDRR97-1).Washington, DC: U.S. Department of Agriculture, Economic Research Service, 2003. 6 p. http://www.ers.usda.gov/publications/rdrr97-1/