That annotation, clipped and functional, hardly suggests what is actually there: a stone-lined shaft dropping around 25 metres into the ground, barely wider than a metre and a quarter across, enclosed within its own small circular stone wall. It is easy to overlook, sitting in the shadow of the tower house, but its positioning is the point.

Tower houses, the compact fortified residences that proliferated across Ireland from the 15th century onward, were built with defence and self-sufficiency in mind. Water supply was not an afterthought. The well at Clomantagh sits at the foot of the base-batter, the outward-splaying slope at the bottom of the tower house wall that helped distribute the building's weight and made it harder to undermine. Its circular stone enclosure measures just under three metres in diameter, a modest but deliberate structure. The well is thought to be contemporary with the 16th-century tower house itself, which also retains its bawn, a defensive walled enclosure of the kind typically built around such structures to protect livestock and provide a defended outer yard. The three elements, tower, bawn, and well, appear to form a coherent ensemble, planned together as a working domestic compound rather than accumulated piecemeal over time.