On state park land
Permission needed
Written permission from Fish, Wildlife and Parks, covering state parks, wildlife management areas and fishing access sites.
Almost every other site still cites a Montana rule that was repealed in 2023. The number below is the current one.
1. The rule, in full
Montana – ARM 12.12.106 (NOT 12.8.802, which is repealed)
Operative text, from FWP's current public use rules page:
It is prohibited to "use a mineral or metal detector, magnetometer, or other metal detecting device at public use sites without written permission from the department."
Scope, from the same page: the public use rules apply to "state parks, wildlife management areas (WMAs) and fishing access sites (FASs)".
Determination: FWP public use sites only. Does NOT reach municipal parks.
This is the Utah trap again, and it is the reason rule 11 exists. Every secondary source found for Montana cites ARM 12.8.802. That rule was repealed. The Montana Administrative Register adoption notice for MAR Notice 12-603 (16 November 2023) repealed the entire 12.8.2xx and 12.8.8xx public-use series and adopted a consolidated 12.12.1xx series in its place, effective 13 January 2024. Property Disturbance moved from 12.8.802 to 12.12.106, where subsection (1)(c) was "adopted as proposed".
Citing 12.8.802 today would publish a rule number that no longer exists – the second confirmed instance of the failure rule 11 was written for, and the first one found by looking rather than by accident.
The substance also changed, and in the detectorist's favour. The repealed rule was read by secondary sources as a flat ban. The current rule is a written permission requirement. FWP said so directly in its response to comment 18 on the rulemaking:
"The public use rules require written permission to use a mineral or metal detector, magnetometer, or other metal detecting device at public use sites. This requirement ensures that these activities are not conducted in locations that could damage sensitive cultural, heritage, or natural resources."
So permit_required, not prohibited.
Limitation to record. The consolidated ARM could not be read directly. rules.mt.gov was rebuilt on a JavaScript platform and every legacy endpoint (ruleno.asp, showrulefile.asp) now 301s to the site root, so the text above rests on FWP's current rules page plus the official Register adoption notice, not on a consolidated read. The rule number comes from the Register, which is primary for the adoption; the operative words come from the agency. Under rule 11 that pairing is acceptable but not ideal, and it should be re-read against the consolidated ARM before this entry is published.
Sources: fwp.mt.gov conservation/wildlife-management-areas/public-use-rules; Montana Administrative Register 12-603 adoption notice, fwp.mt.gov (final_12-603adp_11.16.2023.pdf), parsed locally. Checked 19 Sep 2026.
2. Cities in Montana that publish a rule
Awaiting review. None of the city or county rows publishes until its status is set and its quotation chosen by hand.
3. County rules
Awaiting review. None of the city or county rows publishes until its status is set and its quotation chosen by hand.
4. Cities checked — no published rule
Awaiting review. None of the city or county rows publishes until its status is set and its quotation chosen by hand.