Sec.  73.205   Zones.

   For the purpose of allotments and assignments, the United States is divided
   into three zones as follows:

   (a) Zone I consists of that portion of the United States located within the
   confines of the following lines drawn on the United States Albers Equal Area
   Projection Map (based on standard parallels 291/2 ° and 451/2 °; North
   American datum): Beginning at the most easterly point on the State boundary
   line between North Carolina and Virginia; thence in a straight line to a
   point on the Virginia-West Virginia boundary line located at north latitude
   37 °49' and west longitude 80 °12'30"; thence westerly along the southern
   boundary lines of the States of West Virginia, Ohio, Indiana, and Illinois
   to a point at the junction of the Illinois, Kentucky, and Missouri State
   boundary lines; thence northerly along the western boundary line of the
   State of Illinois to a point at the junction of the Illinois, Iowa, and
   Wisconsin State boundary lines; thence easterly along the northern State
   boundary line of Illinois to the 90th meridian; thence north along this
   meridian to the 43.5 ° parallel; thence east along this parallel to the
   United States-Canada border; thence southerly and following that border
   until it again intersects the 43.5 ° parallel; thence east along this
   parallel to the 71st meridian; thence in a straight line to the intersection
   of the 69th meridian and the 45th parallel; thence east along the 45th
   parallel to the Atlantic Ocean. When any of the above lines pass through a
   city, the city shall be considered to be located in Zone I. (See Figure 1 of
    Sec. 73.699.)

   (b) Zone I-A consists of Puerto Rico, the Virgin Islands and that portion of
   the State of California which is located south of the 40th parallel.

   (c) Zone II consists of Alaska, Hawaii and the rest of the United States
   which is not located in either Zone I or Zone I-A.

   [ 29 FR 14116 , Oct. 14, 1964, and  31 FR 10125 , July 27, 1966, as amended at
    48 FR 29504 , June 27, 1983]