BLM land: the detector is named, and permitted

The Bureau of Land Management holds about 245 million acres, most of it in the western states where detecting and prospecting actually happen. It is the largest single landholder a detectorist is likely to stand on, and the federal rule that governs it names metal detectors and permits them.

That is the opposite of what the other two federal rules in this directory do. In a national park, 36 CFR 2.1(a)(7) bans possessing the detector at all. On national forest land, 36 CFR 261.9 does not mention detectors and reaches what you dig or take. A reader who learns the national park rule and assumes federal land is uniformly closed is wrong about 245 million acres.

This page is the base layer only. Where it stops, it says so.

First: the citation everyone gives you does not exist

Every secondary source that discusses this cites "43 CFR 8365.1-5". If you look for part 8365, you will not find it.

There is no part 8365 in the current Code of Federal Regulations. The eCFR structure for title 43, subtitle B, chapter II, subchapter H contains parts 8340 (Off-Road Vehicles), 8350 (Management Areas) and 8360 (Visitor Services), and nothing else. A request for ecfr.gov/current/title-43/part-8365 returns 404, and so does the full subchapter path.

8365 is a subpart inside Part 8360. So the rule is real, the number is real, and the citation is unusable as a route to it. The working location is:

43 CFR Part 8360, "Visitor Services" - subpart 8365, section 8365.1-5. ecfr.gov/current/title-43/subtitle-B/chapter-II/subchapter-H/part-8360

This matters more than a pedantic point about numbering. A reader doing the right thing – refusing to take a web page's word for it and going to look at the regulation – hits a dead end and may reasonably conclude the rule was invented. It was not. It is one level up from where the citation points.

What the rule says

43 CFR 8365.1-5, "Property and resources": "(a) On all public lands, unless otherwise authorized, no person shall;
(1) Willfully deface, disturb, remove or destroy any personal property, or structures, or any scientific, cultural, archaeological or historic resource, natural object or area;
(2) Willfully deface, remove or destroy plants or their parts, soil, rocks or minerals, or cave resources, except as permitted under paragraph (b) or (c) of this paragraph; or
(3) Use on the public lands explosive, motorized or mechanical devices, except metal detectors, to aid in the collection of specimens permitted under paragraph (b) or (c) of this paragraph."

Read (a)(3) carefully, because it is doing something narrow. It is not a general permission to detect. It is a prohibition on using devices to collect specimens, with the metal detector carved out of that prohibition. The detector is the one listed device you may use for collecting what paragraphs (b) and (c) permit.

So the structure is: (b) says what you may collect, and (a)(3) says you may use a detector to help you do it.

43 CFR 8365.1-5(b): "Except on developed recreation sites and areas, or where otherwise prohibited and posted, it is permissible to collect from the public lands reasonable amounts of the following for noncommercial purposes:
(1) Commonly available renewable resources such as flowers, berries, nuts, seeds, cones and leaves; (2) Nonrenewable resources such as rocks, mineral specimens, and semiprecious gemstones; (3) Petrified wood as provided under subpart 3622 of this title; (4) Mineral materials as provided under subpart 3604 of this title; (5) Forest products for use in campfires on the public lands. Other collection of forest products shall be in accordance with the provisions of part 5500 of this title; and (6) Common invertebrate and plant paleontological resources as provided under part 49 of this title."

Three limits inside that sentence, all easy to read past:

• "Except on developed recreation sites and areas." Campgrounds and developed sites are outside paragraph (b) entirely, and 8365.2 carries separate rules for them.
• "Or where otherwise prohibited and posted." This is the hook the supplementary rules below hang on.
• "Reasonable amounts … for noncommercial purposes." Collecting to sell or barter to a commercial dealer needs a contract or permit under paragraph (c).

The gap, stated as a gap

Rockhounding with a metal detector is expressly contemplated by this rule. (a)(3) permits the device and (b)(2) permits "rocks, mineral specimens, and semiprecious gemstones". Nothing about that is ambiguous.

A coin, a relic, a ring and a buried cache are in neither permitted list. Paragraph (b) is renewable plant material, rocks, minerals, gemstones, petrified wood, mineral materials and common invertebrate fossils. A silver dime is not a mineral specimen. A dropped wedding ring is not a nonrenewable resource. Paragraph (c) is about selling to commercial dealers and does not help either.

And the prohibition in (a)(1) does not obviously reach them either. It covers "any personal property, or structures, or any scientific, cultural, archaeological or historic resource, natural object or area". A historic relic is a historic resource and is plainly caught. A coin lost last summer is somebody's personal property, which is caught too, though "willfully deface, disturb, remove or destroy" is not an obvious fit for picking up a lost coin and the rule was not written with that case in mind.

So the honest answer is that the text does not clearly address modern lost property on BLM land, in either direction. It is not listed as collectable, and it is not clearly prohibited.

This directory is not going to resolve that for you, because the text does not resolve it. What can be said without inventing anything:

• Using the detector is permitted by (a)(3) and does not depend on what you find.
• Anything historic or archaeological is prohibited by (a)(1), and ARPA reaches it separately with far heavier consequences. See the ARPA explainer.
• Rocks, minerals and gemstones are permitted in reasonable amounts for noncommercial purposes, outside developed sites, where not posted.
• Modern lost property sits in a gap. If you want certainty, the route is "unless otherwise authorized" in (a): ask the field office that manages the ground. A written answer from them is worth more than any reading of this page. This is the same gap the "you may sweep, you may not take" explainer describes for other bodies. It recurs because rules about resources were written to protect resources, and a lost earring is not a resource.

The penalty

43 CFR 8360.0-7, "Penalties": "Violations of any regulations in this part by a member of the public, except for the provisions of 8365.1-7, are punishable by a fine not to exceed $1,000 and/or imprisonment not to exceed 12 months. Violations of supplementary rules authorized by 8365.1-6 are punishable in the same manner."

Note the second sentence. A supplementary rule made by a BLM State Director carries the same criminal penalty as the regulation itself. That is why the next section matters.

The layer this page does not cover: supplementary rules

The federal rule above is not the whole answer, and anyone who presents it as the whole answer is leaving out the part most likely to catch you.

43 CFR 8365.1-6, "Supplementary rules": "The State Director may establish such supplementary rules as he/she deems necessary. These rules may provide for the protection of persons, property, and public lands and resources. No person shall violate such supplementary rules.
(a) The rules shall be available for inspection in each local office having jurisdiction over the lands, sites or facilities affected; (b) The rules shall be posted near and/or within the lands, sites or facilities affected; (c) The rules shall be published in the Federal Register; and (d) The rules shall be published in a newspaper of general circulation in the affected vicinity, or be made available to the public by such other means as deemed most appropriate by the authorized officer."

Three things a reader should take from that:

1. They are made by a State Director, and they apply to particular ground. Not nationally. A supplementary rule is issued for a field office, a group of field offices, a national monument, or a named area inside one. The BLM has published 257 Federal Register documents using the phrase. A sample of actual titles, to show the shape:

So the answer varies by where you are, on two separate axes: which field office manages the ground, and whether the ground carries a designation such as a national monument.

2. Some of them do address detecting. This directory has not read them all yet, and says so below. But they exist: a Federal Register full-text search of BLM documents returns 11 for "metal detectors", 5 for "metal detector" and 2 for "metal detecting device", including the Cotoni-Coast Dairies rule and the Colorado River Valley rule.

3. They are findable, which is unusual. Paragraph (c) requires publication in the Federal Register. That is one free, searchable, authoritative publisher covering every supplementary rule in the country. Nothing else in this directory is centrally published like that – state rules sit on fifty different platforms and city rules sit on thousands.

What to do with that as a reader. Before detecting on BLM ground, search federalregister.gov for the field office or monument name plus "supplementary rule". If one exists for your ground, it is law and it carries the $1,000 and 12 months in 8360.0-7. If nothing comes back, the base rule above is your answer. And search several words, not one: "metal detect" as a phrase returns zero results, while "metal detectors" returns eleven.

State law still applies on top

43 CFR 8365.1-7, "State and local laws": "Except as otherwise provided by Federal law or regulation, State and local laws and ordinances shall apply and be enforced by the appropriate State and local authorities. This includes, but is not limited to, State and local laws and ordinances governing: (a) Operation and use of motor vehicles, aircraft and boats;
(b) Hunting and fishing; (c) Use of firearms or other weapons; (d) Injury to persons, or destruction or damage to property; … (j) Forest products; and
(k) Caves."

Antiquities statutes are not in that list, and this provision is carved out of the penalty section in 8360.0-7, so do not read it as making your state's detecting rule federally enforceable. Read it as the reason your state page still matters when you are on federal ground.

The supplementary rules that name a detector, read 20 October 2026

This is the layer that overrides everything above for particular ground, and it is not uniform. Of the 257 BLM supplementary rules in the Federal Register, 46 matched a detecting-related term; all 46 were retrieved in full from the federalregister.gov API and read. Nine name a detector. Six of those nine are final and in force; three are proposals or a draft plan.

The six final ones do four different things, which is the point:

1. Use prohibited outright.

Colorado River Valley, Grand Junction and Kremmling Field Offices, and the Dominguez-Escalante National Conservation Area, Colorado - Final Supplementary Rule, 89 FR 103663, 19 Dec 2024, document 2024-30218: "(13) You must not use a metal detector."

Thirteenth in a numbered list of prohibitions, no permission route stated in the provision. The same rule separately provides "(5) You must not dig in or level the ground at any campsite."

2. Possession prohibited, in the national park formula.

Cotoni-Coast Dairies Unit of the California Coastal National Monument - Final Supplementary Rule, 29 Apr 2024, document 2024-08608: "Possession or use of a mineral or metal detector, magnetometer, side scan sonar, other metal detecting device, or sub-bottom profiler is prohibited."

Read that against 36 CFR 2.1(a)(7) and it is the same sentence. BLM has adopted the National Park Service's formula verbatim for this unit, down to the sub-bottom profiler. So the one place a reader can be sure a BLM detector prohibition reaches possession rather than use is where BLM has borrowed the park wording. The preamble gives the reason as minimising visitor-use conflicts, alongside prohibitions on unattended property, structures and signs.

3. Use prohibited, with a written-permission route.

Lake Havasu Field Office, Arizona and California - Notice of Final Supplementary Rules, 25 Sep 2009, document E9-23247: "The use of metal detectors without written permission is prohibited."

Fort Meade Recreation Area, South Dakota - Supplementary Rules, 10 Aug 2006, document E6-12927: "The use or possession afield of metal detectors within the Fort Meade Recreation Area is prohibited."

Carrizo Plain Natural Area, California - Supplementary Rules, 17 Oct 1997, document 97-27615: "The use of metal detectors is prohibited, except for approved administrative purposes."

Fort Meade reaches possession afield, not only use. Carrizo Plain's only exception is administrative, which is not a route a member of the public can take; Lake Havasu's written permission is.

4. Expressly permitted, with one carve-out.

BLM Arizona, statewide, recreational mineral collecting - Establishment of Supplementary Rules, 2 Jan 1998, document 97-34152. Condition 4 of the collecting rules reads: "Collection, excavation or removal are not aided with motorized or mechanical devices, including heavy equipment or explosives. Metal detectors are acceptable, with the exception of the San Pedro National Conservation Area."

Note where that sentence sits. It is a clarification inside the no-mechanical-aid condition: a detector is not one of the prohibited mechanical devices. So Arizona BLM land is the clearest express permission in the whole supplementary layer, and it is scoped to recreational mineral collecting rather than to detecting generally.

The three that are not in force

• Cotoni-Coast Dairies, proposed rule 29 Nov 2022, document 2022-25810 – carries the same possession sentence and was superseded by the 2024 final rule above.
• Lake Havasu, proposed rules 4 Mar 2008, document E8-4120 – the predecessor of the 2009 final rule, same sentence.
• Medford District, Oregon, draft Resource Management Plan amendment and environmental assessment, 3 Jun 2016, document 2016-13130: "No metal detectors or digging, scraping, disturbing, or removing natural land features for any purpose." This is a draft plan, not a supplementary rule, and it should not be cited as one.

Digging and collecting, across the same 46

Collecting is mentioned in 44 of the 46, which is unsurprising: these are mostly rules about recreational collecting, and a mention is not a prohibition. A digging or excavation prohibition appears in four, two of them final:

Humboldt Field Office, Nevada - Final Supplementary Rules, 8 Jul 2008, document E8-15172: "You must not possess, destroy, deface, dig, or remove petrified wood, common invertebrate fossils, rocks or minerals without a permit in an area otherwise closed to collecting these resources."

plus the Colorado campsite provision quoted above. The other two are proposals (Palm Springs area, 2014; the Humboldt predecessor, 2007).

What this changes about the headline on this page

Nothing about the base layer, and a great deal about reading it alone. 43 CFR 8365.1-5(a)(3) still names the detector and still permits it, and that is still true of most BLM ground. But "or where otherwise prohibited and posted" in paragraph (b) is not decoration – it is the hook these rules hang on, and six of them are hanging on it right now, two adopted in 2024. On the units named above the base permission is gone, and in one case so is the right to have the detector with you at all.

The practical instruction is unchanged and is now better founded: ask the field office that manages the ground. What the sweep adds is that the answer genuinely varies by unit, so a confident answer about "BLM land" as a category is wrong wherever one of these rules applies.

Where this page stops

Read from the eCFR, 43 CFR Part 8360, "Visitor Services", in full. www.ecfr.gov, direct fetch, 132,910 bytes, 24,905 characters extracted, 8 Oct

• Source note in the part: 48 FR 36384, 10 Aug 1983, as amended through 87 FR 47329, 2 Aug 2022. Supplementary rule counts and titles come from the federalregister.gov public API, Bureau of Land Management as the agency filter, queried 8 Oct 2026. The 46 detecting-related supplementary rules were retrieved in full text from the same API and read on 20 Oct 2026; every quotation in the section above is from the document cited with it. Not established, and recorded as unread rather than guessed:
• The 46 detecting-related supplementary rules have now been read – see the section above. What remains unread is the rest: 211 of the 257 did not match a detecting term and were not retrieved. A rule can restrict ground without using any of the words searched for, so the absence of your field office from the list above is not a finding that it permits detecting.
• 43 CFR Part 7, the Department of the Interior's regulations implementing ARPA, which carries the permit and penalty detail for archaeological resources on BLM land. Not fetched.
• 43 CFR 8364.1, temporary closure and restriction orders. This is a second way the answer can change for particular ground, separate from supplementary rules, with penalties under 18 U.S.C. 3571. Seen in the part's contents, not read.
• Subpart 3622 (petrified wood) and subpart 3604 (mineral materials), both incorporated into paragraph (b) by reference.
• Whether a given supplementary rule is still in force. A later rule can supersede an earlier one for the same area.
• Wilderness, Wilderness Study Areas and National Conservation Areas carry their own designations and were not examined. Tribal land is not BLM land and is not covered anywhere in this directory. See the note on that on any state page.

A shared explainer. It is linked from every state page that invokes it and is never restated inline, so one correction here fixes every page that depends on it.

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