Castletown House, Cottlestown, Co. Sligo

The taller three-bay western portion sits under corrugated iron, while the longer eastern range keeps its original hipped slate roof, complete with a brick corbelled chimneystack and clay ridge tiles. Look closely at the east gable of the west range and there is a telling scar: a mark in the stonework suggesting the eastern range once carried a steeper roof than the one it has now, evidence of alteration that most passers-by would never think to seek out in what looks, at first glance, like an unremarkable agricultural building.

Built around 1800 as a corn mill, the structure belongs to a period when landed estates across Ireland invested heavily in processing the grain grown on their tenanted lands, and its scale and finish speak to that investment. The walling is uncoursed rubble limestone, functional rather than decorative, but the window and door openings tell a different story: square-headed windows dressed in ashlar (finely cut and finished stone, reserved for the parts of a building meant to be seen and admired), and segmental headed doorways and carriage openings framed in twice-rebated ashlar surrounds, the rebating cut to receive doors or shutters flush against the stone. A timber eaves beam runs the length of the east range, carried on horizontal roof ties that project outward as corbels, a small piece of structural carpentry left visible rather than hidden. Some of the original timber sash windows survive, including one six-paned example, though on the west range several openings have been infilled and others left without windows at all, the wear of two centuries showing unevenly across the building's length.

The mill's working core has long since given way to storage, the eleven bays now serving as an agricultural store rather than a place of grinding and milling, but the shell survives largely intact. A grass-covered courtyard lies to the south, bounded by rubble stone walls, and the whole complex is reached by a lane from the south, with the ruins of O'Dowd's Castle standing to the north as a reminder of the older lordship whose lands this later industrial building once served.