42 CFR 5a.3 - Definition of Underserved Rural Community.
Underserved Rural Community means a community:
(a) Located in:
(1) A non-Metropolitan County or Micropolitan county; or
(2) If it is within a Metropolitan county, all Census Tracts that are assigned a Rural-Urban Commuting Area (RUCAs) codes of 4-10; or
(3) Census Tracts within a Metropolitan Area with RUCA codes 2 and 3 that are larger than 400 square miles and have population density of less than 30 people per square mile; and
(b) Located in a current:
(1) Federally-designated Primary Health Care Geographic Health Professions Shortage Area, (under section 332(a)(1)(A) of the Public Health Service Act) or
(2) Federally-designated Medically Underserved Area (under section 330(b)(3) of the Public Health Service Act).