The ringfort at Ballynamuddagh has been so thoroughly levelled over the centuries that its outline is now best read not by walking it, but by studying aerial photographs, where it appears as an oval cropmark, a faint shadow pressed into the grass by what once stood there. Cropmarks of this kind form when buried features, old banks, ditches, or foundations, affect how plants grow above them, revealing hidden archaeology most clearly in dry summers when the ground is under stress. It is a peculiar reversal: the less visible a monument becomes at ground level, the more legible it can become from the air.

Ringforts, known in Irish as raths or lios, were the most common form of rural settlement in early medieval Ireland, typically consisting of a circular or oval area enclosed by one or more earthen banks with an external ditch, called a fosse, designed to define and defend a farmstead. This example at Ballynamuddagh was recorded on the Ordnance Survey six-inch map of 1840 as a circular enclosure, and by the time the twenty-five-inch edition was published in 1897 it had acquired the placename annotation 'Lisheen', a diminutive of 'lios', suggesting local memory of its character had persisted even as the physical structure deteriorated. By that later survey it measured approximately 57 metres north to south and 58 metres east to west, enclosed by a bank with an external fosse running from the southeast around to the northwest. A drainage ditch subsequently cut through the eastern side, truncating the monument further. A second enclosure lies approximately 160 metres to the north, hinting that this was once a more populated corner of the landscape.

The site sits in pasture immediately west of a conifer plantation, which helps orient a visitor on the ground, though there is little to see without prior knowledge of what to look for. Aerial imagery, including orthophotos taken between 2005 and 2012 and an ASI aerial photograph from January 2003, shows the oval outline of the levelled enclosure with reasonable clarity, and a shed-like structure is visible on the northern edge of what remains of the enclosing element in more recent imagery. Anyone approaching this site on foot should do so with a downloaded aerial image for comparison, since the surface traces are subtle and the drainage ditch on the eastern side has obscured what would otherwise be the clearest portion of the monument's perimeter.