Where most examples of the type describe a reasonably circular enclosure, this one is noticeably elongated, measuring roughly 42.5 metres east to west but only 24.7 metres north to south, giving it an irregular, almost compressed outline. A rath, to use the Irish term, is a ringfort defined by an earthen bank and ditch rather than stone, and here the bank survives in a continuous arc running from the east, around the south, and up to the north-north-west. Elsewhere the boundary is formed by a natural or modified scarp, a drop in the ground that performs the same enclosing function.

The monument is in fair condition, though quarrying at the north-west has bitten into it, removing part of whatever once stood there. Two gaps in the earthwork, one at the south-east and one at the south-south-west, are both assessed as modern, yet either could plausibly reflect the position of an original entrance, a common feature on the southern or eastern side of ringforts. Inside the enclosure there is evidence of a probable souterrain, an underground stone-lined passage or chamber of the kind frequently associated with Irish ringforts, likely used for storage or as a place of refuge. A second ringfort lies only 180 metres to the west-north-west, suggesting that this part of Lisnamoltaun was once a more densely settled landscape than the quiet fields would now imply.