Idaho Code § 58-804
Every person, association or company claiming to be entitled to such lands, or to any block, lot, share or parcel thereof, must, within sixty (60) days after the first publication of such notice, in person or by duly authorized agent or attorney, sign a statement in writing containing an accurate description of the particular parcel or parts in which he claims to have an interest, and the specified right, interest or estate therein, which he claims to be entitled to receive, also a brief statement of the facts upon which such right, interest or estate depends for its validity, and deliver the same to such corporate authorities or judge, and all persons failing to sign and deliver such statement, within the time specified in this section, are, as against any claimant, forever barred the right of claiming or recovering such lands, or any interest therein. In case any lots, pieces or parcels of land remain unclaimed and unconveyed at the end of said sixty (60) days, all such lots shall revert to and become the property of such town.
Idaho Code § 58-804