Idaho Code § 70-1103
Any petition for the formation of a port district may describe a district of less area than the county in which such petition is filed, and in such event the county commissioners shall fix a date for hearing on such petition and publish a notice of such hearing once a week for two (2) successive weeks prior thereto in a newspaper of general circulation within such county. After such hearing, the county commissioners may increase or diminish the boundaries of such proposed port district and shall thereafter submit to vote the proposition of the formation of such port district. The same procedure for notice and election shall be followed as is prescribed for the formation of a port district having boundaries co-extensive with the county boundaries, except that the election shall be confined solely to the lesser port district; and provided, that whenever two (2) or more petitions for the formation of a port district shall be filed as herein provided, the petition describing the greater area shall supersede all others and an election shall first be held thereon, and no port districts shall ever be created within the limits, in whole or in part, of any existing port district.
The boundaries of all port districts shall follow county precinct lines, so that such districts shall include only whole voting districts.
Idaho Code § 70-1103