Idaho Code § 34-435: Cancellation of registrations following any general election of those not voting for four years.

Within one hundred twenty (120) days following the date of the general election, the county clerk shall examine the election register and the signed statements of challenge made at that election. After this examination, the county clerk shall immediately cancel the registration of any elector who did not vote at any election in the past four (4) years.

This section shall be construed as to provide for a uniform four (4) year registration period for all electors.