Idaho Code § 31-412

When an election has been held, as in this act provided, and the county board of canvassers in each of said counties have found and declared that two-thirds (2/3) of the voters in each county who have voted for or against such consolidation have voted in favor of such consolidation, then, on and after the second Monday in December next thereafter, said counties are consolidated under the name of the county with which such consolidation was effected, and the county consolidated shall, on and after said date, cease to exist. Where such consolidation occurs, the terms of office of all county officers in the county which has been consolidated shall automatically terminate.