Every office on this page was opened and checked on Oct. 22, 2026.
The 399 underground mine openings in Ohio are spread across 88 counties, and the heaviest of them is Gallia County with 58. 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.
Coverage is automatic in the 26 mandatory counties (Athens, Belmont, Carroll, Columbiana, Coshocton, Gallia, Guernsey, Harrison, Hocking, Holmes, Jackson, Jefferson, Lawrence, Mahoning, Meigs, Monroe, Morgan, Muskingum, Noble, Perry, Scioto, Stark, Trumbull, Tuscarawas, Vinton, Washington) and optional in 11 more.
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 This is information, not a guarantee: the two federal files can be wrong, incomplete or out of date, the boundaries and the geocoder can be wrong, a point is a location and not a property line, and nothing on this page says that a mine is or is not under any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.