FieldFindersThe toolkit
Ten map layers drawn from the same federal survey data the agencies publish, and one thing no other app has: the right to dig what you are looking at.
01 · The map
Every layer here is live, and every source named is the real one behind it. Toggle them together, set the opacity, and stack terrain on history on geology until the ground tells you where to spend the day.
See through the trees
Laser terrain survey strips away vegetation and crops and leaves the shape of the ground itself. Old road cuts, terracing, mill races, ploughed-out foundations and the faint rectangles where buildings stood read clearly from above when they are invisible standing in the field. Flip between grey relief and warm coloured relief, and push the exaggeration until the ground gives it up.
USGS Shaded Relief, with coloured terrain from MapTiler
Where things used to be
A century and more of topographic quads, so you can see the settlement that is now a wood, the road that became a track, the schoolhouse, the mill and the crossing that the modern map forgot. Most productive private ground in the East is productive because something stood on it before 1900.
USGS historical topographic quadrangles
Named, mapped, tappable
Every listed site on the National Register, plotted and named. Tap one and you get what it is. Use it to work out what the ground around your booking was doing when it mattered, and to understand the context of what comes out of it.
National Register of Historic Places
Where history concentrates
The same register read as a density map rather than a list of pins, so whole districts light up. It answers a question a pin cannot: which parts of this county were busy, and which were always empty.
National Register density
The layer that keeps you legal
Federal land, drawn. The Archaeological Resources Protection Act makes excavation on federal ground an offence, and National Park Service units prohibit detecting outright. This layer shows you where that starts, so a boundary you could not see on the ground is one you can see before you set off.
Bureau of Land Management Surface Management Agency
The lie of the land
Contours, watercourses, tracks and structures at survey grade. The everyday layer for reading approach, drainage and where people would sensibly have walked.
USGS Topo
What is there now
Current aerial imagery, for crop marks, standing cover, gates, tracks and working out where you can actually park.
USGS imagery
What is under the coil
Surface geology and lithology, which decides how deep your machine sees, how the ground behaves after rain and whether mineralisation is going to fight you all day.
Macrostrat lithology
One toggle, three sources
Waterways, recorded mine sites and a gold density heat map built from the federal mineral resources record, filtered to gold and weighted by whether a site actually produced. Tap any point for the name and its producer status. This is the layer with no British equivalent at all.
USGS NHD waterways and USGS Mineral Resources Data System
18,607 settlements that are gone
Named places the map no longer shows: the villages, mills, stations and post office hamlets that emptied out and were dropped from the record. Most productive private ground in the East is productive because something stood on it, and this is the fastest way to find out what.
USGS GNIS
Where the line used to run
4,042 out of service segments and 128,688 sidings and spurs. A siding is a place where men stood around, loaded, waited and dropped things, and a lifted line leaves an embankment that is invisible at ground level and obvious from above.
Federal Railroad Administration via USGS, and OpenStreetMap
The twelve national routes
All 12 National Historic Trails, drawn end to end. Migration, military and trade routes with two centuries of loss along their length, and a way of understanding why an empty field was once somewhere people passed through daily.
National Park Service
185,688 of them, mapped
Family plots, meeting house yards and burying grounds, including many that no longer have a stone standing. This layer is here to be avoided, not searched. A burying ground tells you a settlement was close, and the settlement is the target.
USGS GNIS and the National Register
Massachusetts and Connecticut
3,880,005 parcels with the owner named on each, read live from the state GIS office that publishes them. Two states so far, not the whole country. Knowing who owns a field is not permission to be on it, and every parcel says so.
MassGIS and the Connecticut Office of Policy and Management
Connecticut and Rhode Island
Field boundaries that have not moved since they were built, mapped from LiDAR. A stone wall in second growth forest is the edge of a farm that stopped being a farm, and the cellar hole is usually not far from where two of them meet.
The Connecticut stone wall mapping project, and RIGIS with the University of Rhode Island
What people said happened here
Local history, folklore and the stories attached to a place. Not evidence, and not treated as evidence, but a lead worth reading before you spend a day on a field.
Wikidata and Wikipedia
Building by building, 14 cities
60 Sanborn fire insurance volumes, which map towns lot by lot with the construction of every building on them. Baltimore and Washington DC on the East Coast. Nothing else shows a vanished urban block in this much detail.
Library of Congress
The ground before the development
Historical aerial photography going back decades. Demolished farmhouses, former fairgrounds, old river crossings and racetracks are all visible in an image taken before the subdivision went in.
USGS EROS: Aerial Photo Single Frames, NHAP and NAPP
Coastal and inland losses
Recorded wreck positions around the coast. Context for a beach, and a reminder that anything on the seabed or in state waters is governed separately and usually closed.
NOAA
Where the fighting actually was
Studied battlefield boundaries, which matter in both directions: they tell you what happened on the ground, and the federally administered ones are closed to detecting outright.
National Park Service American Battlefield Protection Program
What the ground will have done to it
Soil survey under any field. Acidity and drainage decide whether iron survives at all and how deep a copper coin has travelled, so it tells you what to expect before you swing.
USDA SSURGO
Real tiles, no signal needed
Four layers over an area you choose, downloaded as real map tiles rather than screenshots, so you pan and zoom in a field with no bars. Unlimited areas and no cap from us. A single field at close detail is about 8MB, a wide area at full detail about 105MB, and the panel tells you the size and your free space before it starts.
Downloaded to the device
Georeference your own, unlimited
Pin your own historical map, estate plan or hand drawn sketch to the ground and it sits under everything else as a layer. Unlimited uploads, free, and the images never leave your device.
Your own files, held on the device
The answer, not the layer
Reads the protected, restricted and federal layers under wherever you are looking and tells you what that ground is before you drive to it. The rest of this list shows you what happened somewhere. This one tells you whether you are allowed to be there.
FieldFinders, reading the layers above
Boundaries you can work to
Field and parcel boundaries drawn over everything else, so the area you have booked has an edge you can navigate to rather than a rough idea.
OpenStreetMap
02 · On the ground
The other half is turning up somewhere you are allowed to be, with a document that proves it, and leaving with a record of what came out.
The part no other app has
Every mapping app in America will hand you layers and leave you to knock on doors. FieldFinders is the only place where you research the ground and secure the right to dig it without leaving the app. Land is listed by the people who own it, with a day rate, the acreage, what is on it and the days they allow.
Written permission in your pocket
Every confirmed booking generates a signed search agreement carrying both names, the dates, the boundary and what happens to anything you find. If somebody asks what you are doing on that land, you open your phone. It is also the document that settles a disagreement about finds months later.
Coverage tracking
Track where you have actually swung across a session, so you finish the field instead of walking the same forty yards four times. Over several visits it builds a real coverage picture of ground you know.
Ask the map a question
Tap anywhere and pull together what every active layer says about that spot: terrain, geology, what was there historically, what is nearby on the register, and whether you are anywhere near restricted ground.
Your record, and the landowner’s
Log what came out of the ground with a photograph and the spot it came from, held against the booking so both sides have the same record. The United States has no national scheme to send finds to, which is exactly why keeping your own record matters.
03 · Recording what you find
Britain has a national archaeological database and a Treasure Act, and our UK app works against both. The United States is built differently: recording here is yours to do, and what you keep is what exists. That makes the finds log and the written agreement the two documents that matter, rather than a form sent to a national scheme.
What replaces them is your own record and the written agreement. Log what you find against the booking, and if something is genuinely significant, report it to the State Historic Preservation Office, which records rather than confiscates. The Finds and Ethics Code sets out how.
04 · What it costs
The research platforms sell a subscription for the map layers. Detector Maps, the most complete of them, charges $59.99 a year or $7.99 a month for Explorer and $99.99 a year or $11.99 a month for Pro. We carry more than they do and charge nothing for any of it, because the layers are not the product. The service fee comes off a booking, if you make one.
Two layers are state by state as they roll out: parcels with owner names covers Massachusetts and Connecticut, and stone walls covers Connecticut and Rhode Island. LiDAR relief is at its strongest across the East Coast, which is the ground we sell.
| What you get | Detector Maps | FieldFinders |
|---|---|---|
| Historic map sheets | 9,500 | 208,437 |
| National Historic Trails | 9 | All 12 |
| LiDAR hillshade and terrain relief | Advanced tier on Pro | Yes, free |
| Historical aerial photography | No | Yes, free |
| Sanborn fire insurance maps | No | 60 volumes, 14 cities |
| Lost places and vanished settlements | Yes, paid | 18,607, free |
| Historic railways, sidings and spurs | Yes, paid | 128,688 sidings, free |
| Burying grounds | No | 185,688, free |
| Stone walls mapped from LiDAR | No | Yes, in Connecticut and Rhode Island |
| Protected and restricted land drawn | No | Yes, free |
| Geology and soils under the field | No | Yes, free |
| Heritage density | No | Yes, free |
| Parcel boundaries with owner names | Yes, on Pro | Yes, in Massachusetts and Connecticut |
| Offline maps in the field | Yes, paid | Yes, free and uncapped |
| Georeference your own maps | 10 on Explorer, unlimited on Pro | Unlimited, free |
| Tells you whether you may detect there | No | Yes |
| Land you are allowed to detect on | No | Yes, listed by the owner |
| The landowner’s written permission | No | Yes, before you travel |
| A search agreement for every visit | No | Yes |
| Terms on finds agreed in advance | No | Yes, in the agreement |
| Price of the research tools | $59.99 to $99.99 a year | Free |
| Price if you never get onto any land | The same | Nothing |
Prices read from Detector Maps’s published pricing page in September 2026 and correct then. Tiers change, so check theirs before relying on ours. Everything in their column is what their own pricing page says they include.
04 · Questions
208,437 historic map sheets, drawn from the USGS Historical Topographic Map Collection, the Library of Congress Sanborn collection and USGS EROS aerial photography, together with 60 Sanborn fire insurance volumes covering 14 cities including Baltimore and Washington DC. All of it free. The layers are queried live from the publishing source each time the map moves rather than served from a snapshot we hold.
In Massachusetts and Connecticut, yes. FieldFinders reads 3,880,005 parcels with the owner named on each, live from MassGIS and the Connecticut Office of Policy and Management, which publish them as open public records. Connecticut carries a parcel collection year of 2026 and Massachusetts updates municipality by municipality rather than to one statewide date. Knowing who owns a field is not permission to be on it, and every parcel in the app says so.
Yes. Offline area downloads four layers over ground you choose as real map tiles rather than screenshots, so you can pan and zoom in a field with no bars. There is no cap on how many areas you save and no storage limit imposed by us. A single field at close detail is around 8MB and a wide area at full detail around 105MB, and the app shows the tile count, the size and your free space before the download starts.
The research tools on FieldFinders are free. There is no subscription, no trial that expires and no paid tier holding the map layers: LiDAR relief, historical topographic maps, historic sites, protected land and the rest cost nothing whether you book land or not. The only money that changes hands is the day rate a landowner sets for a booking, plus one service fee shown to both sides before anything is confirmed. A paid research subscription keeps charging whether you get onto any land or not.
Yes. FieldFinders carries 23 map layers and charges nothing for any of them: 208,437 historic map sheets against the 9,500 Detector Maps advertises, all 12 National Historic Trails against their 9, plus LiDAR relief, historical aerial photography, 60 volumes of Sanborn fire insurance maps, 18,607 lost places, 185,688 burying grounds, 128,688 rail sidings, geology, soils, protected and federal land, offline maps with no cap, and unlimited georeferencing of your own maps. Parcels with owner names covers Massachusetts and Connecticut, and stone walls covers Connecticut and Rhode Island. The larger difference is that no tier of a research subscription gets you permission to be on the land it points you at, which is what FieldFinders is actually for.
Detector Maps publishes $59.99 a year or $7.99 a month for Explorer, and $99.99 a year or $11.99 a month for Pro, with parcel owner names, GLO patents and the advanced LiDAR held on the Pro tier. Those figures were read from their pricing page in September 2026 and will change, so check theirs. FieldFinders charges nothing for any of its 23 layers, at any tier, and carries more historic map sheets and more National Historic Trails than the paid product. The relevant difference is still not the number: a subscription buys research, and research is not permission to be on the land it points you at.
There is no catch and no trial period. All 23 layers are free because they are not the product. The product is booked permission on private land, and we take a service fee from a booking when one happens. Free tools with nothing to book would be a worse business than a subscription; free tools attached to bookable ground is a better one. Parcels with owner names covers Massachusetts and Connecticut, and LiDAR relief is at its strongest across the East Coast, which is the ground we sell.
FieldFinders is the only app that combines research layers with bookable permission from landowners. It carries USGS LiDAR relief, historical topographic maps, National Register historic sites, federal protected land, geology, satellite and a gold prospecting layer built from USGS mineral records, and it is the only place you can book the legal right to detect the ground you are looking at.
Yes. FieldFinders carries USGS shaded relief and coloured terrain relief, which strip vegetation and crops away and show the shape of the ground. Old road cuts, terracing, mill races and ploughed-out foundations read clearly from above when they are invisible from the field.
FieldFinders draws federal land from the Bureau of Land Management Surface Management Agency data as a map layer. The Archaeological Resources Protection Act makes excavation on federal ground an offence and National Park Service units prohibit detecting outright, so seeing the boundary before you set off matters.
No, and no app can. The United States has no national finds database equivalent to the United Kingdom’s Portable Antiquities Scheme. FieldFinders gives you a private finds log held against each booking instead, and recommends reporting genuinely significant finds to the State Historic Preservation Office.
Every layer above works before you have paid anybody anything.