ARPA Explained: The Archaeological Resources Protection Act for Detectorists

ARPA, the Archaeological Resources Protection Act of 1979, makes it a federal offense to excavate, remove or damage archaeological resources on federal public land or Indian land without a permit. For metal detecting, ARPA matters because it protects items at least 100 years old that are of archaeological interest, while its rules exclude ordinary coins and bullets unless they are found in an archaeological context.

This is general information, not legal advice. Rules change and closures are often local, so confirm with the managing agency before you go.

Many detectorists have heard of ARPA but are unsure what it actually covers. Some think it bans all detecting on federal land; others assume anything under 100 years old is fair game everywhere. Neither is right. This explainer walks through the text of the law and its regulations in plain English, so you can understand where the lines are drawn.

What ARPA covers: ARPA and metal detecting at a glance

The definition of "archaeological resource"

ARPA defines an archaeological resource as any material remains of past human life or activities that are of archaeological interest, as determined by regulation. The statute lists examples including pottery, basketry, bottles, weapons, weapon projectiles, tools, structures, pit houses, rock art, graves and human skeletal remains, or any piece of them. It then sets a firm floor: no item is treated as an archaeological resource unless it is at least 100 years old.

The uniform regulations define "of archaeological interest" as capable of providing scientific or humanistic understanding of past human behavior through scientific study. That is a broad standard. A 120-year-old horseshoe lying in the remains of a homestead could qualify; a modern pull tab never could.

The coin and bullet exclusion

ARPA's savings provisions state that the law does not apply to, or require a permit for, collecting for private purposes any rock, coin, bullet or mineral that is not an archaeological resource as determined by the regulations. The regulations then list coins, bullets and unworked minerals and rocks among items that are not archaeological resources unless found in a direct physical relationship with archaeological resources.

In practice, a stray old coin in an open field is treated differently from a coin lying in the remains of a 19th-century cabin or a battlefield. Context is everything. Remember too that ARPA is a minimum: the Bureau of Land Management's own guidance says historic coins cannot be collected on its land, and the National Park Service prohibits detectors entirely. Agency rules can be stricter than ARPA.

The surface arrowhead provision

ARPA states that its criminal penalty section does not apply to removing arrowheads located on the surface of the ground. This is narrow. It does not authorize digging, it does not override agency regulations that prohibit removing artifacts, and it does not apply to other artifacts. Do not treat it as permission to collect.

What ARPA prohibits

1. Unauthorized excavation or removal. No person may excavate, remove, damage, alter or deface, or attempt to do so, any archaeological resource on public or Indian lands without a permit or exemption.
2. Trafficking in illegally removed resources. No person may sell, buy, exchange, transport or receive an archaeological resource removed from public or Indian lands in violation of ARPA or other federal rules.
3. Interstate trafficking in resources taken in violation of state or local law. This is the provision that can reach finds from private or state land if they were taken illegally under state or local law and then moved or sold across state lines.

ARPA penalties

For a knowing violation, the statute provides criminal fines of up to $10,000 and up to one year in prison. If the commercial or archaeological value of the resources plus the cost of restoration and repair exceeds $500, the maximum rises to $20,000 and two years. A second or subsequent violation carries up to $100,000 and five years.

Federal land managers can also assess civil penalties after notice and an opportunity for a hearing, based on the archaeological or commercial value of the resources and the cost of restoration and repair, with higher penalties for repeat violations. The law also allows forfeiture of the archaeological resources and of vehicles and equipment used in a violation, and it authorizes rewards for people who provide information leading to a penalty or conviction. Your detector, digging tools and even your vehicle can be at stake.

How ARPA works alongside other rules

ARPA does not decide where you can detect. That is set by the land manager's regulations:

• National parks prohibit possessing or using metal detectors.
• National forests prohibit disturbing or removing any prehistoric, historic or archaeological resource, and require a special use permit to search for treasure trove or artifacts. Read more in our guide to metal detecting in national forests.
• BLM land allows casual-use prospecting with detectors but directs visitors to leave cultural artifacts in place. See metal detecting on BLM land.
• State land is governed by state antiquities laws that may protect items younger than 100 years.

ARPA's savings provisions also state that it does not restrict activities permitted under existing laws relating to mining and other multiple uses of the public lands. That is why prospecting for gold under the mining laws continues on open federal land while archaeological sites remain protected.

How to stay well clear of ARPA problems

1. Avoid historic and prehistoric sites entirely on public land: foundations, cabins, mining camps, trash dumps, rock shelters and battlefields. Our Civil War relic hunting guide covers where relic hunting is legal.
2. If you dig a target and see old material around it, stop, refill the hole and note the location.
3. Never buy or sell artifacts with unclear provenance from public land.
4. Report significant finds to the land manager rather than removing them.
5. Join an official program, such as the Forest Service's Passport in Time, if you want to work on historic sites legally.

A detector built for prospecting does not change the rules. Whether you use a basic VLF or one of our professional detectors, the law applies the same way.

Frequently asked questions

Does ARPA make metal detecting illegal?

No. ARPA protects archaeological resources on federal and Indian lands. Whether you may use a detector at a given place is set by the land manager's rules.

Are coins over 100 years old protected by ARPA?

Not automatically. The regulations exclude coins unless they are found in a direct physical relationship with archaeological resources. Agency rules, such as BLM guidance on historic coins, can still prohibit collecting them.

Does ARPA apply on my own land?

Generally not, but its ban on interstate trafficking can apply to items taken in violation of state or local law, and state laws on burials and antiquities still apply.

What are the penalties under ARPA?

Up to $10,000 and one year for a first offense, rising to $20,000 and two years if value and restoration costs exceed $500, and up to $100,000 and five years for repeat offenses, plus civil penalties and forfeiture.

Can I pick up an arrowhead on public land?

ARPA's criminal penalties exclude surface arrowheads, but agency rules on BLM and Forest Service land direct visitors to leave artifacts in place. The safe answer is to leave it and photograph it instead.

Sources

• >16 U.S.C. 470bb, ARPA definitions (GovInfo)
• >16 U.S.C. 470ee, ARPA prohibited acts and criminal penalties (GovInfo)
• >16 U.S.C. 470kk, ARPA savings provisions (GovInfo)
• >43 CFR 7.3, ARPA uniform regulations definitions (Cornell LII)