Provides that in the administration of any Federal assistance program under which such assistance is allocated or apportioned or otherwise made available on the basis of whether the geographic location of a recipient is within or outside a standard metropolitan statistical area, (SMSA), the head of the department or agency carrying out such program may, upon the request of the Governor of the State in which such area is located, modify the geographic boundaries of such area in order to specify the portions of such area which are and which are not essentially metropolitan. Stipulates that (1) such modification shall apply only to the specific program with respect to which the request was made; and (2) no such modification may be made in the case of a standard metropolitan statistical area incorporating all or part of more than one State without the consent of the Governors of all affected States.