Idaho Code § 31-118
Cassia county is described as follows: beginning with the intersection of the center of the main channel of Snake river with the north and south center line of section twenty-eight (28), township ten (10) south, range twenty-one (21) east;
Western boundary. Thence south on the said center line of said section twenty-eight (28), to the point of intersection of the north line of the right of way of the Minidoka & Southwestern Railroad Company, which point is one hundred (100) feet distant at right angles from the center of the main track of the line of road of said railroad company as the same is now located; thence in a southwesterly direction along the north line of said railroad right of way to a point where said line intersects the south line of the canal right of way of the Twin Falls Land & Water Company, which point of intersection is one hundred (100) feet distant at right angles from the center line of the main canal of the said Twin Falls Land & Water Company; thence south to the south line of section thirty-six (36), township ten (10) south, range twenty (20) east; thence west to the southwest corner of said section thirty-six (36); thence south on the section lines to the south line of township eleven (11) south, thence west to the southeast corner of township eleven (11) south, range eighteen (18) east; thence south on the range lines to the south line of the state of Idaho (1907, p. 40);
Southern boundary. Thence east along the south boundary line of the state of Idaho to the intersection of the same with the one hundred thirteenth (113th) meridian west from Greenwich;
Eastern boundary. Thence north along the said meridian to the intersection of the same with the (R.C., section 23i) southern line of township twelve (12) south; thence west upon and along the southern line of said township twelve (12), to the southwest corner of township twelve (12) south, range thirty (30) east; thence north upon the range line between ranges twenty-nine (29) and thirty (30) east, to the southwest corner of township nine (9) south, range thirty (30) east;
Northern boundary. Thence west along and upon the south line of township nine (9) south, to the southwest corner of section thirty-four (34), township nine (9) south, range twenty-eight (28) east; thence north upon and along the line between sections thirty-three (33) and thirty-four (34), township nine (9) south, range twenty-eight (28) east, and an extension thereof to the point where said line so extended intersects the center of the main channel of Snake river (1913, ch. 6, section 2, p. 32); thence down the center of the main channel of said river in a southwesterly direction to the point of beginning (R.C., section 23i).
County seat- Burley.
Idaho Code § 31-118