Is Metal Detecting allowed in Idaho State Parks: YES, when authorized by the Park Manager
See link to rules HERE:
401. OPERATIONAL GUIDELINES FOR NON-TRADITIONAL RECREATIONAL ACTIVITIES.
Non-traditional recreational activities such as model airplane/glider operations, geo-caching, gold panning and metal detecting may be authorized by the Park Manager or his designee, if such activities do not interfere with traditional uses of the park and are consistent with preservation of park resources.
Boise also has a set of rules HERE
Boise City Code authorizes metal detecting in Boise Parks and Recreation facilities with permit from an authorized agent.
FMDAC Disclaimer: FMDAC assumes no responsibility for any person who knowingly or accidentally violates any state park regulation. Although FMDAC will try to keep this information current we cannot anticipate how each regulation will be interpreted by a specific park department, park employee or other government employee. It is the sole responsibility of each individual to know and obey the regulations of the park or area they are visiting and or metal detecting.