(a) For the purpose of allotment and assignment, the United States is divided into three zones as follows: (1) Zone I consists of that portion of the United States located within the confines of the following lines drawn on the U.S. 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 § 73.699 .)(2) Zone II consists of that portion of the United States which is not located in either Zone I or Zone III, and Puerto Rico, Alaska, Hawaiian Islands and the Virgin Islands.(3) Zone III consists of that portion of the United States located south of a line, drawn on the United States Albers Equal Area Projection Map (based on standard parallels 29.50 and 45.50 North American datum), beginning at a point on the east coast of Georgia and the 31st parallel and ending at the United States-Mexican border, consisting of arcs drawn with a 241.4 kilometer (150 mile) radius to the north from the following specified points: | North latitude | West longitude |
| (a) | 29°40'00" | 83°24'00" |
| (b) | 30°07'00" | 84°12'00" |
| (c) | 30°31'00" | 86°30'00" |
| (d) | 30°48'00" | 87°58'30" |
| (e) | 30°00'00" | 90°38'30" |
| (f) | 30°04'30" | 93°19'00" |
| (g) | 29°46'00" | 95°05'00" |
| (h) | 28°43'00" | 96°39'30" |
| (i) | 27°52'30" | 97°32'00" |
When any of the above arcs pass through a city, the city shall be considered to be located in Zone II. (See Figure 2 of § 73.699 .)
28 FR 13660, Dec. 14, 1963, as amended at 33 FR 15422, Oct. 17, 1968; 50 FR 23697, June 5, 1985; 51 FR 44070, Dec. 8, 1986