Idaho Code § 31-117
Caribou county is described as follows: commencing at the northwest corner of township five (5) south, range thirty-nine (39) east of Boise meridian;
Northern boundary. Thence east along the township line between townships four (4) and five (5) south, Boise meridian, to the northeast corner of township five (5) south, range forty-six (46) east, Boise meridian, or to the Wyoming and Idaho state line;
Eastern boundary. Thence south along the Idaho and Wyoming state line to the corner of Bear Lake and Bannock counties;
Southern boundary. Thence in a westerly direction along the line between Bear Lake and Bannock counties to the southwest corner of township nine (9) south, range forty-two (42) east, Boise meridian; thence west along township line between nine (9) and ten (10) south, range forty-one (41) east, to the southwest corner of section thirty-two (32), township nine (9) south, range forty-one (41) east, Boise meridian;
Western boundary. Thence north three (3) miles along section line to the northwest corner of section twenty (20), township nine (9) south, range forty-one (41) east, thence west one (1) mile to the southwest corner of section eighteen (18), township nine (9) south, range forty-one (41) east; thence north nine (9) miles to the northwest corner of section six (6), township eight (8) south, range forty-one (41) east, thence west four (4) miles to the southwest corner of section thirty-three (33), township seven (7) south, range forty (40) east; thence north six (6) miles more or less to the northwest corner of section four (4), township seven (7) south, range forty (40) east; thence west along the line of first standard parallel one and one-half (1 1/2) miles to the southwest corner of section thirty-one (31), township six (6) south, range forty (40) east; thence north six (6) miles to the northwest corner of township six (6) south, range forty (40) east; thence west six (6) miles to the southwest corner of township five (5) south, range thirty-nine (39) east; thence north six (6) miles to place of beginning.
County seat-Soda Springs.
Idaho Code § 31-117