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← Abandoned mines, all states · Mining incidents in Maryland
Abandoned mine inventory

Abandoned mines in Maryland

Maryland has 1,880 mine and prospect features on USGS topographic maps published 1894–1998, including 97 mine openings (shafts, adits and air shafts), across 24 counties. OSMRE's abandoned mine land inventory lists 1,102 problems in the state, 609 of them not yet reclaimed. MSHA's register carries 304 Maryland mines with status Abandoned or Abandoned and Sealed.

Every mine and prospect feature the USGS digitized from historical topographic maps of Maryland, every OSMRE abandoned mine land problem, and every MSHA-registered mine with status Abandoned, by county. Each county page lists the named features and links every MSHA mine to its own record.

Mapped mine features (USGS)
1,880
Mine openings
97
OSMRE problems unreclaimed
609
MSHA mines marked abandoned
304
24 counties with mapped features61 features carry a name0 prospect pitsmaps published 1894–1998 1,102 OSMRE problems, 493 reclaimed280 problem areas (PADs), 190 with work left 5 MSHA mines abandoned and sealed The state program's own inventory estimate: 250 sites (IMCC-NAAMLP Hardrock AML Report 2025, Table 5, page 46).
By countyranked by mapped USGS features
County USGS features Openings OSMRE problems MSHA abandoned
Garrett County
372 64 461 113
Prince George's County
314 0 0 19
Allegany County
148 29 641 62
Anne Arundel County
137 0 0 26
Baltimore County
126 0 0 23
Charles County
120 2 0 5
St. Mary's County
94 0 0 4
Cecil County
83 0 0 8
Harford County
77 0 0 9
Worcester County
77 0 0 5
Montgomery County
44 1 0 4
Washington County
43 1 0 3
Frederick County
32 0 0 5
Queen Anne's County
31 0 0 3
Howard County
27 0 0 3
Calvert County
24 0 0 0
Caroline County
23 0 0 3
Kent County
23 0 0 2
Dorchester County
22 0 0 4
Wicomico County
21 0 0 1
Baltimore city
17 0 0 1
Talbot County
11 0 0 0
Somerset County
8 0 0 0
Carroll County
6 0 0 1
What the features are
  1. Mine openings
    shafts, adits, air shafts, portals and vertical openings: the ways into underground workings
    199 6.7%
  2. Mines and surface workings
    labelled mines, open pits, strip mines, placer and hydraulic workings
    903 30.3%
  3. Quarries, gravel and borrow pits
    construction-material and industrial-mineral extraction
    863 28.9%
  4. Dumps, tailings, spoil and gob
    what mining left above ground
    199 6.7%
  5. Mills, tipples and facilities
    processing plants and hazardous structures
    39 1.3%
  6. Other reclamation problems
    highwalls, subsidence, polluted or clogged water, fires, slides and gases in OSMRE's inventory
    777 26.1%
  7. Other
    symbols outside the classes above
    2 0.1%
By source vocabularythe publishers' own terms
Feature type Features
Disturbed Surface 411
Strip Mine 263
Gravel Pit 212
P3 Water Problems 181
Open Pit Mine or Quarry 150
Gravel Pit 139
Gravel/Borrow Pit - Undifferentiated 133
Sand Pit 102
P3 Mine Opening 100
Adit 96
P3 Gobs 80
P2 Portals 69
Gravel/Borrow Pit - Undifferentiated 63
P2 Dangerous Highwalls 59
P3 Spoil Area 59
P2 Clogged Streams 55
P3 High Wall 49
Sand Pit 45
P2 Dangerous Piles & Embankments 43
Sand and Gravel Pit 43
P2 Polluted Water: Agricultural & Industrial 42
P2 Clogged Stream Lands 39
P2 Hazardous Equip & Facilities 37
Open Pit Mine or Quarry 37
Quarry 34
P2 Dangerous Slides 33
Sand and Gravel Pit 31
Quarry 29
P2 Subsidence 26
P2 Industrial/Residential Waste 26
P3 Industrial/Residential Waste 25
P2 Vertical Openings 22
P1 Dangerous Slides 21
P2 Hazardous Water Bodies 20
Strip Mine 20
Disturbed Surface - Pit 19
P2 Polluted Water: Human Consumption 15
P2 Dangerous Impoundments 15
Borrow Pit 11
P3 Equipment Facility 10
How to read these numbers

A USGS feature is a symbol on a historical topographic map, there when the map was surveyed; it may since have been sealed, reclaimed, built over or reopened, and the map does not say which. An OSMRE row is a problem the abandoned mine land program tracks, not a mine, and several problems make one problem area (PAD), which is the unit a state program counts and reports; the public extract can also hold more problem areas than a state's live inventory, because areas since merged or ruled ineligible stay in the published file, so a state figure that differs from this one is not a contradiction. An MSHA mine is a registered operation whose operator reported abandonment, a record that starts in the 1970s; that is a regulatory status rather than a physical one, and it also holds operations merely between jobs, portable crushers above all, which is why over a thousand mines carrying it have been inspected in the last two years. The three overlap and are never added together. Counties are assigned from each feature's coordinates against the Census 2023 county boundaries. The full method and every source are on the national page.

Sources
  1. USGS, Consolidated Prospect- and Mine-Related Features from 7.5- and 15-Minute Topographic Quadrangle Maps of the United States (USMIN)
    597,612 point and area features digitized from about 106,350 historical topographic maps published 1886–2006; public domain (CC0). A feature is a map symbol, not a field-verified site, and the map does not say whether it was still worked.
  2. USGS Fact Sheet 2025–3003, The Abandoned Mine Inventory of the United States
    States that as of 2025 there is no comprehensive national inventory of abandoned mine features, and that the detailed national database now being built will not be published.
  3. OSMRE, Abandoned Mine Land Inventory System (e-AMLIS), public Problems layer
    One row per abandoned mine land problem in a problem area, with its type, funding program and reclamation status; mostly coal mined before the 1977 Surface Mining Control and Reclamation Act. Coordinates are the problem area's.
  4. MSHA, Mines dataset (Mine Data Retrieval System)
    Every mine registered with MSHA since the 1970s; a mine reads Abandoned or Abandoned and Sealed when its operator reported that status. Refreshed weekly.
  5. US Census Bureau, 2023 cartographic county boundaries (1:500,000)
    Each feature's county is assigned by its coordinates against these boundaries, not copied from the source file.
  6. GAO-20-238, Abandoned Hardrock Mines (March 2020)
    Federal agencies had identified at least 140,000 abandoned hardrock mine features on federal land and estimated more than 390,000 more not yet captured in their databases.
  7. Abandoned Hardrock Mine Reclamation (AHMR) Program, US Department of the Interior
    The program the USGS inventory is compiled for. Its appropriations and the 674,000 field-confirmed feature count on this page were provided by the program manager, Office of Environmental Policy and Compliance, and are cited with permission (2026-09-08).
  8. IMCC-NAAMLP Hardrock AML Report
    Page 48 carries the two figures this page leans on: USGS estimates 633,181 of the 725,690 mine features it recorded from historic topographic maps, 87 percent, are hardrock; and state and federal agencies have submitted more than 724,000 AML features to the national database being built, already more than the historic maps hold. Year-by-year AHMR funding is on page 35.