Idaho Code § 31-5807

A county, by charter, may have and exercise all of the powers, duties, privileges and rights available to a county under the constitution and laws of the state of Idaho. The enumeration of powers in a charter shall not expand the county’s powers granted by the constitution or laws of the state of Idaho, nor shall a charter limit or prohibit the performance of duties required to be performed by the county under the constitution or laws of the state of Idaho. In the event of any conflict between the provisions of a charter and the provisions of the constitution or statutes of the state of Idaho, or the United States, the constitution and statutes shall prevail.