Abandoned mines in the United States

No federal count exists. USGS's 2025 fact sheet says that as of 2025 there is no comprehensive national inventory of abandoned mine features, and that the detailed database USMIN is building for the Interior Department will not be published, because agencies do not want individual workings locatable. GAO reported in 2020 that federal agencies had identified at least 140,000 abandoned hardrock mine features on federal land and estimated more than 390,000 more not yet in any database.

Each figure here is a count of records in a named public inventory. A USGS feature is a symbol on a historical topographic map: an adit, a shaft, a prospect pit, a quarry. It was there when the map was surveyed; it may since have been sealed, reclaimed, built over, or reopened as a working mine, and the map does not say which. An OSMRE row is a problem the abandoned mine land program tracks, not a mine, and one mine can produce several. An MSHA mine is a registered operation whose operator reported abandonment, which is why that record starts in the 1970s and misses everything earlier.

Counties are assigned from coordinates. Every feature is placed in a county by its location against the Census 2023 county boundaries rather than by the county name in the source file, which is missing, truncated or wrong on a few thousand rows. Mapped areas are located by their centroid.

The three records overlap and do not reconcile. A sealed shaft can appear as a USGS symbol, an OSMRE vertical-opening problem and an MSHA abandoned mine at once. The pages never add them into one number.