Metal Detecting in Montana

1. The rule, in full

Montana – ARM 12.12.106 (NOT 12.8.802, which is repealed)

Read from the Montana Administrative Register adoption notice MAR 12-603 (fwp.mt.gov, final_12-603adp_11.16.2023.pdf, parsed locally), and the rule's citation, title and placement confirmed against the official Administrative Rules of Montana at rules.mt.gov. The current public use rules page at fwp.mt.gov supplies the detector sentence and is labelled as the agency's wording, for the reason given below. Checked 3 Oct 2026.

Re-read 3 Oct 2026. The previous version put FWP's web-page wording in the operative-text slot and took its scope from the same page. The rule's own lead-in and its authority are now quoted from the Register, and what remains outstanding is named precisely rather than papered over.

Confirmed against the official ARM at rules.mt.gov: rule 12.12.106 is titled "PROPERTY DISTURBANCE" and sits in Title 12 Fish, Wildlife and Parks, Chapter 12.12 Recreational Land Use, Subchapter 12.12.1 Public Use.

Operative lead-in and structure, from the adoption notice, NEW RULE VI (ARM 12.12.106):

"(1) While in a public use site it is prohibited to:
(a) damage, deface, destroy or possess any natural features, developed features, or vegetation;
(b) damage, deface, destroy, possess, or permit the disturbance or removal of topsoil or subsoil, nonfossilized and fossilized paleontological specimens, cultural or archeological resources, or the parts thereof;
(c) is adopted as proposed.
(d) design, develop, construct, place, or occupy any structure … (1)(e) through (2) are adopted as proposed." AUTH: 23-1-102, 23-1-106, 23-1-111, 87-1-201, 87-1-301, 87-1-303, MCA. IMP: the same sections.

"While in a public use site" is the scope, and it is the rule's own words – better than the agency page's gloss that the rules "apply to state parks, wildlife management areas (WMAs) and fishing access sites (FASs)", which is a description of what public use sites are rather than the operative phrase.

Subsection (1)(c) is the detector provision, and it is the one the adoption notice does not reproduce. "Adopted as proposed" means its text sits in the proposal notice, MAR Notice 12-603, published 8 September 2023 at page 952 of the 2023 Montana Administrative Register, Issue No. 17. That document has been identified and not yet retrieved: rules.mt.gov has moved to a search application whose legacy endpoints – ruleno.asp, showrulefile.asp, showNoticefile.asp – all now redirect to an 894-byte shell, and its document viewer could not be deep-linked to the rule text.

So this is what the detector requirement says, on the agency's wording and labelled as such, pending that proposal notice. FWP's 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."

The adoption notice independently confirms the substance in FWP's own response to comment, which refers to "a mineral or metal detector, magnetometer, or other metal detecting device at public use sites". Two official documents agree on the requirement; what is missing is the enacted paragraph verbatim.

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

1 city in Montana publishes a rule we can quote, out of 7 checked.

Of the 7 checked, 4 had pages on the city’s own site that we found and read. For the other 3 we could not locate a municipal source, so nothing is claimed about them either way.

3. County rules

No county check has been run for Montana. That is not a finding that Montana’s counties publish no rules. It means the question was never asked here, and this directory does not assert an answer it has not looked for. The county sweep covered 21 states; Montana was not one of them.

4. Cities checked - no published rule

6 cities in Montana were checked and have no published rule on this page. Of those, 6 returned no rule, and 0 did return something that has not been published – mostly rules that turned out to govern county land, which are in the county section above. A city here is not a city where detecting is allowed. It is a city whose own published material did not answer the question.

All 6 were checked on 13 September 2026, in one sweep, so that date applies to every row.

5. Land this page does not cover

This page answers for Montana state land, and for city and county land where the state rule reaches it. Several other kinds of ground are not covered here, and naming them is more honest than letting a reader assume the page is complete.

Tribal land. This directory does not cover it, and will not.

There are 574 federally recognised tribal nations. Each is a sovereign jurisdiction with its own law, its own permitting, its own enforcement and its own cultural-resource provisions, and none of them is answered by a state's code or by any federal rule quoted on these pages. A one-line instruction to "get tribal permission" would be worse than this paragraph, because it implies one process and one authority where there are 574. If you are on or near tribal land, the governing law is that nation's, and the place to ask is that nation's own offices. Nothing on this page applies there.

BLM land is covered, partly, in its own place. The Bureau of Land Management holds about 245 million acres and the federal rule names metal detectors and permits them, which is the opposite of the national park rule. See BLM land: the detector is named, and permitted. That page covers the base regulation; it does not yet cover the supplementary rules individual BLM State Directors issue for particular field offices.

Named and not examined. These are recorded so their absence is visible rather than silent. No claim is made about any of them:

• Military withdrawn land, including ranges and training areas.
• Bureau of Reclamation land, which surrounds a great many reservoirs.
• Water district and irrigation district land.
• Wilderness, Wilderness Study Areas and National Conservation Areas, which carry designations of their own. And one general point about signs. The commonest piece of reasoning in this subject is "there was no sign, so it was allowed." Arizona's State Land Department answers it in writing, in condition 2 of its own Recreational Permit terms:

"You will comply with all laws, rules, regulations and ordinances. Posting is not required for these provisions to be enforceable."

That is Arizona's sentence about Arizona's provisions and this directory does not present it as the law of any other state. But the proposition it states is the one to carry: nothing read for this project makes a published rule's enforceability depend on a sign at the boundary. Where posting does matter, a specific provision says so, and that provision is quoted on the page where it occurs.