The theory is that the recess, set at ground level on the north side of the interior, gave flour sacks room to bulge outward as they were filled, a modest but deliberate piece of design. The tower stands on the crest of a low hill in Cullenstown, about 180 metres back from the shoreline at the eroding entrance to Ballyteige Lough in County Wexford, and it has been sitting there, largely unnoticed, long enough to appear on the Ordnance Survey six-inch map of 1839.

The Civil Survey of 1654 to 1656 records a mill at Cullenstown, most likely the property of Thomas Cullin of nearby Cullenstown Castle, though the survey does not specify what kind of mill it was. Whether the structure visible today is the same one, or a later replacement on the same site, is not clear. What survives is a cylindrical stone tower three storeys tall, with an external diameter of 5.3 metres and an interior of just 3 metres across, rising to a height of 5.3 metres. The western doorway remains open, wide enough to pass through comfortably, while the eastern one is blocked. Internal stairs are formed from single stones projecting from the inner face of the wall, rising from the west doorway to the second floor. The floor levels were carried on rebates, shallow ledges cut into the inner face of the masonry, and narrow slit windows, only about 15 centimetres wide, provided minimal light on each storey. It is a compact, efficient structure, built to do a specific job in a coastal landscape where wind off the sea would have been a reliable resource.