Idaho Code § 50-1303
The centerline intersections and points where the centerline changes direction on all streets, avenues, and public highways, and all points, witness corners and reference points on the exterior boundary where the boundary line changes direction shall be marked with magnetically detectable monuments the minimum size of which shall be five-eighths (5/8) of an inch in least dimension and two (2) feet long iron or steel rod unless special circumstances preclude use of such monument and all lot and block corners, witness corners and reference points for lot and block corners shall be marked with monuments conforming to the provisions of section 54-1227, Idaho Code. Monuments shall be marked such that measurements between them may be made to the nearest one-tenth (0.1) foot. All lot corners of a burial lot within a platted cemetery need not be marked with a monument, but the block corners shall be monumented in order to permit the accurate identification of each burial lot within the cemetery. The monuments shall conform to the provisions of section 54-1227, Idaho Code. The locations and descriptions of all monuments within a platted cemetery shall be recorded upon the plat, and the courses and distances of all boundary lines shall be shown, but may be shown by legend. The survey for any plat shall be conducted in such a manner as to produce an unadjusted mathematical error of closure of each area bounded by property lines within the survey of not more than one (1) part in five thousand (5,000).
Idaho Code § 50-1303