Maryland Abandoned Mine Maps

Every office on this page was opened and checked on Oct. 22, 2026.

The 97 underground mine openings in Maryland are spread across 22 counties, and the heaviest of them is Garrett County with 64. An opening on a historical sheet is a shaft, an adit or a tunnel that was drawn where the surveyor found it, so it marks a way into workings that run on underground, away from the point.

Maryland's coal mining is confined to Allegany and Garrett Counties.

No guarantee

Everything here can be wrong. This is information, not a guarantee: the two federal files can be wrong, incomplete or out of date, the boundaries and the geocoder can be wrong, a point is a location and not a property line, and nothing on this page says that a mine is or is not under any particular property. Do not buy, sell, move, or make any decision about a home or about your safety on this alone. Ask the state mine map office named here for the maps, and have a qualified engineer look at the ground.

MDE Mining Mapping, historic underground coal mine repository (Deep Mine Mapping Application) is the state route in Maryland. MDE's online repository of historic underground coal mines built with Maryland Environmental Services, the State Archives and Frostburg State University, opened through the Deep Mine Mapping Application at plus KMZ files of mine sites.

OSMRE National Mine Map Repository is the federal archive. It holds maps of more than 275,000 closed and abandoned mines, the images are not downloadable, and they are sent on request: search the repository by state, county, company or mine name, then ask for the sheet by its number through the map request form or at nmmr@osmre.gov.

A mine map is the only document that shows the rooms, the pillars and the depth of cover under a given piece of ground. A point in either federal file is a location, not a property line, and it says nothing about what lies under any particular house.

Maryland runs no state mine subsidence insurance programme. Cover, where an insurer offers it at all, is an endorsement on a homeowner policy, and a standard policy excludes earth movement, which is what mine subsidence is.

Ask your own insurer in writing whether the policy covers subsidence from mining, and keep the answer. Seven states run a programme of their own: Pennsylvania, Ohio, West Virginia, Kentucky, Indiana, Illinois and Wyoming, with a protection programme in Colorado.

The topographic file holds 1,004 mapped mine features inside Maryland, 97 of them underground openings. The sheets they were drawn on were surveyed between 1942 and 1998. The commonest kinds are gravel/borrow pit, open pit mine or quarry and gravel pit.

The mineral file holds 813 worked or prospected sites in Maryland, 812 of them named, with 761 sites recorded as a past producer. The commodities most often named are iron, sand and gravel and stone.

How the counting was done: every point in both files was placed inside the Census TIGER 2024 county and place boundaries by its own coordinates, not by the county name written in the file, because that name is blank or wrong often enough to matter. A point that falls outside every boundary is counted in no county and no town.

What the counts are not: a count of mines under houses. A single opening can lead to workings that run for miles, and a working with no opening on a sheet is in no count at all. Only a mine map shows the rooms, and only the offices named above hold the maps.

No guarantee

Everything here can be wrong. This is information, not a guarantee: the two federal files can be wrong, incomplete or out of date, the boundaries and the geocoder can be wrong, a point is a location and not a property line, and nothing on this page says that a mine is or is not under any particular property. Do not buy, sell, move, or make any decision about a home or about your safety on this alone. Ask the state mine map office named here for the maps, and have a qualified engineer look at the ground.