This is not a castle, a church, or a field boundary. It is what remains of a blast furnace, and it speaks to an industry that most people would not associate with the Kerry landscape at all.

The structure dates to the seventeenth century and formed the core of what was known as the Blackstones Iron Works, which operated for over eighty years, from around 1670 until 1754. A blast furnace of this period was a substantial technological installation: iron ore, charcoal, and limestone would be charged in from the top, with bellows forcing air through the base to achieve the temperatures needed to smelt the metal. Here the furnace was built directly into the hillside slope, a typical arrangement that allowed workers to load materials from the higher ground to the east, where traces of the access ramp are still visible. The furnace itself is roughly square in plan, measuring about 7.2 metres north to south and 7 metres east to west. The western wall survives to around five metres in height, while the northern and eastern walls have largely collapsed. At the southern face, the remains of a casting arch can still be made out, a splayed opening roughly 4.4 metres wide and 2 metres high, with fragments of the wedge-shaped voussoir stones that once formed its curve visible at the western side. Ruined houses, presumably those of the workers or miners, stand about 50 metres to the south.

The site sits in open pasture near the Caragh River, and the surviving wall, the scattered ironwork, and the ghost of that casting arch give a surprisingly tangible sense of what industrial production looked like in early modern Kerry, tucked into a hillside far from any obvious centre of trade or manufacture.