Idaho Code § 31-108
Bingham county is described as follows: beginning at the northwest corner of section thirty-one (31), township six (6) south, range thirty (30) east:
Southern boundary. Thence east along the section line between sections thirty-one (31) and thirty (30), township and range aforesaid, and an extension thereof to the point where such extended line intersects with the center of the west channel of Snake river; thence up the center of the west channel of Snake river and the center of the main channel of Snake river to the intersection of the township line between townships four (4) and five (5) south; thence east along the said township line between townships four (4) and five (5) south to the southwest corner of township four (4) south, range forty-two (42) east;
Eastern boundary. Thence north along the range line between ranges forty-one (41) and forty-two (42) east to the southeast corner of township one (1) south, range forty-one (41) east;
Northern boundary. Thence west along the township line between township one (1) and township two (2) south, to the southwest corner of township one (1) south, range forty (40) east; thence north along the range line to the base line; thence west along the base line to the southwest corner of township one (1) north, range thirty-eight (38) east; thence north along the range line to the northeast corner of section twenty-four (24), township one (1) north, range thirty-seven (37) east; thence west along section lines to the southwest corner of section fifteen (15), township one (1) north, range thirty-seven (37) east; thence north along the section line to the northwest corner of said section fifteen (15), township one (1) north, range thirty-seven (37) east; thence west, following the section lines to the range line between ranges thirty-three (33) and thirty-four (34) east; thence north to the south line of Jefferson county; thence west along the south line of Jefferson county to the southeast corner of township four (4) north, range thirty-one (31) east; thence westerly along said township line seven and eighty-one hundredths (7.81) chains to the closing corner of sections three (3) and four (4), township three (3) north, range thirty-two (32) east, Boise meridian;
Western boundary. Thence south along section lines to the corner of sections three (3), four (4), thirty-three (33) and thirty-four (34), townships two (2) and three (3) north, range thirty-two (32) east; thence west along the township line to the corner of townships two (2) and three (3) north, ranges thirty (30) and thirty-one (31) east, Boise meridian; thence south along the range line to the corner of township two (2) north, ranges thirty (30) and thirty-one (31) east, Boise meridian; thence west along the township line to the closing corner of sections three (3) and four (4), township one (1) north, range thirty (30) east; thence south along the section lines to the standard corner of sections thirty-three (33) and thirty-four (34), township one (1) north, range thirty (30) east; thence west to closing corner of sections three (3) and four (4), township one (1) south, range thirty (30) east; thence south along section lines to the corner of sections three (3), four (4), thirty-three (33) and thirty-four (34), townships one (1) and two (2) south, range thirty (30) east; thence west along said township line to the corner of townships one (1) and two (2) south, ranges twenty-nine (29) and thirty (30) east, Boise meridian; thence south along the range line between townships twenty-nine (29) and thirty (30) east, to place of beginning.
County seat-Blackfoot.
Idaho Code § 31-108