The wall, the western gable of what was once a rectangular building, is 6.5 metres wide and still carries a square window just below its apex, at what would have been second storey or attic level. Two metres to its east, the stream continues flowing northward, as it always has, and the closeness of that gable to the water makes clear that the mill building once straddled the stream entirely, using its flow to drive the machinery within.

The Strafford Inquisition of County Mayo, a survey of landholdings conducted under the authority of Thomas Wentworth, Earl of Strafford, during the 1630s, records the place as Bellaghowly and lists among its assets a castle, land measured in quarters and cartons, and a cornmill described as adjoining. That pairing of mill and castle was not unusual for the period; tower houses, the compact fortified residences that dot the Irish landscape from the later medieval centuries onward, were frequently the centres of small agricultural economies, and a working mill was a valuable asset. Ballyhowley Castle itself stands approximately 150 metres to the north. By 1838, when the first edition of the Ordnance Survey six-inch map was completed, the mill building was still standing and was recorded as an east-west rectangular structure straddling the stream, its name lettered clearly on the sheet.

What remains today is built of mortared stone, and the slight returns of both the north and south walls at either side of the gable give a sense of where the rest of the building once extended eastward over the water. The mill no longer appears on modern maps as a functioning structure, reduced now to this one standing face looking out over grazing land, its window open to the sky.