Administrative rules or codes are officially enacted agency regulations that have the force and effect of law. These rules elaborate on the requirements of a law or policy. Each state has its own set of administrative rules/codes which are passed by the state legislature.
Example: Admin. Rules Mont § 12.8.202 is a Montana Department of Fish, Wildlife and Parks regulation regarding the use of weapons and fireworks in state parks.
12.8.202 WEAPONS AND FIREWORKS
(1) No person may discharge any firearm, fireworks, explosives, air or gas weapon, or arrow from a bow, on or over either land or water, from April 1 to the opening date of archery season each year, unless the designated area is otherwise posted. Areas, or portions of areas, may be closed to shooting when the director determines there is undue hazard to human life or property. In addition to any other penalties provided for violation, the participant may be expelled from the area.