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 deg. 
and 451/2 deg.; 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 deg.49' and west longitude 
80 deg.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 deg. 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 deg. 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]