Idaho Code § 6-107
The said sheriff making such sale shall make as many certificates of such sale as there are counties in which such real property is situated, adding a sufficient number to deliver one to each purchaser of such real property. The sheriff shall deliver one of such certificates to each purchaser of such real property, and shall file one with the county recorder of the county where such sale was made; and he shall also send one to each of the county recorders of the several counties in which any portion of said real estate is situated, by United States mail, prepaying the postage thereon. Such certificates of sale shall be filed and recorded by the several county recorders as is now provided by law in sales of real property under execution.
Idaho Code § 6-107