Idaho Code § 44-1005
No person not a citizen of the United States, or who has not declared his intention to become such, or who is not eligible to become such, shall be employed upon any state or municipal works; nor shall any such person be employed by any contractor to work on any public works of the state or any municipality: provided, that any state prisoner may be employed within the state prison grounds and as provided in section 3, article 13, of the constitution. Any person who shall violate any of the provisions of this section, on conviction thereof, shall be punished by a fine of not less than ten dollars ($10.00) nor more than $100 for each person so employed, or by imprisonment in the county jail until such fine be paid or until discharged as provided by law.
Idaho Code § 44-1005