They are found in exurb an, rural, or agricultural areas.
Word Origin and History for exurb
"the outer, prosperous ring of the suburbs," 1955, American English, from exurban (adj.), by 1838 (it seems to have arisen in the writings of the reform movement focused on getting cemeteries out of cities), from ex- + urban, on model of suburb. Related: Exurbanite; exurbia.