Idaho Code § 26-301

No bank shall maintain any branch except as provided for in this act. Any bank organized and chartered under the laws of Idaho may, upon written application to and with the approval of the director, establish and operate one (1) or more branches for the transaction of its business at any location. Any such bank may establish and operate a branch in a state other than Idaho, provided that the bank shall comply with all applicable provisions of Idaho law, the law of the other state and federal law. Any bank organized and chartered under the laws of another state or under federal law may establish and operate one (1) or more branches in Idaho as permitted by chapter 16, title 26, Idaho Code, and federal law.