Idaho Code § 40-1615: Petition for annexation.

(1) The proceedings for inclusion shall be initiated by petition of twenty per cent (20%) of the qualified electors in the area proposed to be annexed to and included within the highway district. The petition shall accurately describe the boundaries of the area to be annexed, and shall state the name and identify the highway district to which the annexation is sought, and shall be accompanied by a map showing and distinguishing the boundaries of the highway district and the boundaries of the area proposed to be annexed to the highway district.

(2) Proposals for the annexation of territory consisting entirely of public lands, or of a combination of public lands and privately held lands but which have no qualified electors to initiate a petition, may be initiated by petition of the highway commissioners of the district to which the proposed annexation is to be made.