Idaho Code § 40-614

At least thirty (30) days before the commissioners of a particular county shall proceed to do any work in any adjoining county, it shall cause a notice to be served, in writing, on the chairman or clerk of the commissioners of the adjoining county of its intent to do the work, describing the nature, scope and kind of work to be done, giving the approximate cost of the work, the place where the work is to be performed, the approximate time the work will be commenced and the approximate time that will be required to complete the work.