Idaho Code § 67-205
In the event in the enactment of legislation creating legislative and representative districts for the election of senators and representatives, any election precinct has been omitted from any legislative and/or representative district or has been included in more than one legislative and/or representative district, the county commissioners of the county in which any such precinct is located are authorized and directed to make such changes as are hereinafter provided. If an omitted precinct is located entirely within a district, it shall be included in such district. If an omitted precinct borders on two (2) or more districts, it shall be included in the district which has the smaller number of registered voters. If a precinct has been included in more than one legislative or more than one representative district, it shall be removed from the district or districts which have the larger number of registered voters, provided, however, that such precinct must be contiguous with the legislative and representative district with which it is included.
Idaho Code § 67-205