Idaho Code § 31-857
Whenever any school district, road district, herd district, or other district has heretofore been, or shall hereafter be, declared to be created, established, disestablished, dissolved, or modified, by an order of the board of county commissioners in any county of the state of Idaho, a legal prima facie presumption is hereby declared to exist, after a lapse of two (2) years from the date of such order, that all proceedings and jurisdictional steps preceding the making of such order have been properly and regularly taken so as to warrant said board in making said order, and the burden of proof shall rest upon the party who shall deny, dispute, or question the validity of said order to show that any of such preceding proceedings or jurisdictional steps were not properly or regularly taken; and such prima facie presumption shall be a rule of evidence in all courts in the state of Idaho. No challenge to the proceedings or jurisdictional steps preceding such an order, shall be heard or considered after seven (7) years has lapsed from the date of the order.
Idaho Code § 31-857