A holy well, by its usual logic, should hold water, and the devotional life that once gathered around such sites depended on that water, whether for curing ailments, marking patterns, or simply touching. This one, a circular stone-lined shaft just over half a metre across and less than a metre deep, sits in pasture at the base of a north-facing slope in Ballygreighan, and holds nothing. Twelve metres to the north-west, a natural spring still emerges from the hillside and flows into a small pool, which makes the well's emptiness feel less like abandonment and more like a quiet shift in the landscape over time.

The name Tobercahillboght appears on Ordnance Survey six-inch maps from 1837 and again on those of 1913, indicating that the site was recognised and named across at least two generations of cartographic record. "Tobar" is the Irish word for well, and the fuller name likely preserves a local personal or place name now otherwise untraced. The well itself is carefully made, its steep sides and floor dressed with stone, suggesting it was constructed with some deliberate effort rather than simply cleared from natural ground. Two metres to the east, a crucifix plaque rests within a small circle of stones, a modest arrangement that signals the site's continued, if low-key, religious significance even after the water receded.