Idaho Code § 70-1203
At the same election at which the proposition is submitted to the voters as to whether a port district shall be formed, three (3) commissioners shall be elected to hold office, respectively for the terms of two (2), four (4) and six (6) years. All candidates at the formation election shall be voted upon by the entire port district, and the candidate residing in commissioner district number one (1) receiving the highest number of votes shall hold office for the term of six (6) years; and the candidate residing in commissioner district number two (2) receiving the highest number of votes shall hold office for the term of four (4) years; and the candidate residing in commissioner district number three (3) receiving the highest number of votes shall hold office for the term of two (2) years. In all subsequent elections in the county of original formation, the port commissioners shall likewise be elected at large within that area of such county embracing the port district.
Idaho Code § 70-1203