What makes it worth a second look is partly what remains and partly what has been lost: the enclosing bank, which once ran around the full perimeter of the site, survives well only along the northern arc, while elsewhere it has been almost entirely levelled, leaving the interior as a subtly uneven platform roughly 34 metres north to south and 36 metres east to west.

This is a rath, the Irish term for a ringfort, a class of monument built in their thousands across Ireland during the early medieval period, roughly between the fifth and twelfth centuries. Raths were typically enclosed farmsteads, their earthen banks defining the boundary of a household rather than a military fortification in the modern sense. The one at Barbavilla retains an additional internal feature that adds a layer of interest: in the south-east quadrant, a separate earth and stone bank runs roughly east to west, approximately ten metres long and over four metres wide, curving slightly northward at its eastern end. Its function is not recorded, but secondary banks within ringfort interiors are occasionally associated with subdivided enclosures or later modifications to the original structure. There is also a slight depression in the south-west quadrant of the interior, and the perimeter has been quarried into at both the west and south-east, which accounts for some of the damage to the outer bank and complicates any reading of the original form.