Lidarman can tell you where something interesting might be. It has no idea whether you're allowed to dig there — that's a separate question, and it depends entirely on who owns or manages the land.
In short
This is general background, not legal advice, and it isn't a substitute for checking the specific rules that apply to a specific parcel. Private land, public land, and protected historical/archaeological sites are three genuinely different situations with different rules — treating them as interchangeable is the most common way hobbyists end up in trouble.
Working out where to ask permission? Scan the area first — try the free demo first, no account.
1. Private land
The rule here is simple even though tracking down the right person isn't always: get explicit permission from the actual current owner before you set foot on the property, every time, regardless of whether it looks abandoned or unused. "It didn't look like anyone was using it" is not permission, and is the single most common way this hobby gets a bad name with landowners.
County assessor / GIS parcel viewers are usually free and public, and are the standard way to identify the current owner of a specific parcel.
Ask in person or in writing, and be upfront about what you're doing — most refusals come from vague or evasive asks, not from the activity itself.
Get permission in a form you can point back to later (a text message, an email, a signed note) if the property is one you'll want to return to.
Fill every hole, pack out anything you dig up that isn't yours to keep, and leave the property in the condition you found it — this is both common courtesy and often a condition landowners assume even when they don't say it out loud.
2. Public land
"Public" doesn't mean "open to detecting" — rules vary enormously by which agency manages the specific land, and treating all government-owned land as one category is a mistake:
National Park Service land — metal detecting and artifact collection are prohibited in essentially all National Park Service units, full stop. This covers a lot more ground than the name "national park" suggests — national battlefields, national monuments, and national historic sites are also NPS units.
National Forest & BLM land — generally more permissive than NPS land for casual detecting in many areas, but rules vary by the specific forest, district, or field office, and some areas require a permit. Disturbing a site with known historical or archaeological significance remains off-limits regardless.
State parks & state land — varies by state; often prohibited or permit-only, sometimes allowed in designated areas only.
City & county parks — varies locally; check with the specific parks department rather than assuming.
The pattern across all of these: ask the specific agency that manages that specific parcel, rather than assuming a rule you've heard applies everywhere applies here too.
3. Protected and archaeological sites
Beyond ordinary land-use rules, sites with recognized archaeological or historical significance often carry additional legal protection layered on top, regardless of which agency owns the land. In the US, the federal Archaeological Resources Protection Act makes it a federal crime to excavate, remove, or damage archaeological resources on federal and Native American land without a permit, and many states have their own similar antiquities statutes covering state and, in some cases, private land where sites are formally recorded. A site doesn't have to be famous or marked with a sign to be legally protected — that's exactly why the desk research described in finding old homestead sites is worth doing before you go, not just after.
4. About the battlefield presets in the tool
Worth reading if you've used them
Lidarman's search tool includes a dropdown of well-known American battlefields — Gettysburg, Antietam, Shiloh, and others — as convenient, historically interesting coordinates to point the terrain visualization at. Nearly all of them are protected National Park Service units, where metal detecting and artifact recovery are prohibited. They're included as compelling examples of what LIDAR terrain analysis can reveal, not as a suggestion that they're places to dig. If a search leads you to want to visit a site like these in person, that's a trip for looking, not digging.
5. Before-you-go checklist
Confirmed current land ownership for the specific parcel (county GIS/assessor records)
Contacted the owner or managing agency directly and gotten explicit permission
Checked whether the site has any known historical or archaeological designation
Know the plan for anything you find — some finds (particularly anything that could be human remains, burials, or clearly significant artifacts) come with their own separate reporting obligations regardless of whose land you're on
More guides
Finding Ghost Towns With LIDAR — What a vanished town leaves in the ground, where the list of 16,525 of them comes from, and why the dot is only a starting point.
Detecting Near Civil War Battlefields — The protected core is off limits — the study area around it often isn't. How to tell the two apart before you knock.
Finding Old Mining Camps — 44,677 abandoned metal mines, what the camp left behind as opposed to the workings, and why the two are a short walk apart.
Finding Old Homestead Sites With LIDAR — What a vanished foundation, root cellar or filled-in farm road looks like in elevation data, and how to tell them from natural ground.
Historical Maps for Metal Detecting — Where to get old maps free, what the symbols mean, and how to line a century-old sheet up with the ground you are standing on.
Detecting Along the Westward Trails — What survives of the Oregon, California, Pony Express and Santa Fe routes, and how ruts and swales read in terrain data.
Once you know where you're allowed to look, Lidarman helps you narrow down where within it to focus.