It points to iron-working activity that, by the early nineteenth century, had already left enough of a mark on the local geography to shape place names and appear on the earliest detailed maps of the country.

The iron works in question belonged to the Nesbitts of Derrycarne, a family with interests in Annaghduff parish who were operating some form of iron production before 1830, though exactly when they began is no longer known. Whether the works were centred on what is now the townland of Furnace, or slightly displaced toward the nearby village of Dromod, remains uncertain. What is clear is that by the time the Ordnance Survey produced its six-inch map of the area in 1835, a structure described as an old furnace was already being recorded in Furnace or Bleankinnew townland, just north of the village. The word "old" in that 1835 notation is telling: even at the point of first detailed cartographic survey, the furnace was already being treated as something historic, a remnant rather than a working feature of the landscape.