Small enough that anyone passing through would have to stoop, the opening measures roughly 80 centimetres high and 40 centimetres wide, and behind it lies a well. What makes it worth a second look is the stonework framing it: a cut-stone surround with a pointed chamfered arch, the chamfer being a bevelled edge worked into the stone to soften the right angle, a technique associated with late-medieval craftsmanship. The arch and its surround appear to have been lifted from an earlier structure and reset here, which is what earns it the designation of architectural fragment rather than original feature.

Late-medieval stonework of this kind in Ireland typically dates from somewhere between the thirteenth and sixteenth centuries, a period when skilled masons were producing decorative details for churches, tower houses, and monastic buildings across Munster. When such buildings fell into ruin or were demolished, their dressed stonework was frequently salvaged and put to use elsewhere, built into field walls, farmyard enclosures, or, as here, repurposed to frame a functional opening. The fragment at An Sliabh Riabhach almost certainly had a prior life in a more formal architectural setting before finding its current role giving dignified access to a roadside well.