Code of Federal Regulations Title 43. Public Lands:  Interior § 43.2650.5–2 Rule of approximation

To assure full entitlement, the rule of approximation may be applied with respect to the acreage limitations applicable to conveyances and surveys under this authority, i.e., any excess must be less than the deficiency would be if the smallest legal subdivision were eliminated (see 62 I.D. 417, 421).