It is not immediately obvious as an ancient monument. The bank has been broken by cattle, gapped in multiple places, and weathered down to a modest rise of about a metre on its outer face. Yet the geometry persists: an interior space measuring approximately 28 metres north to south and 27 metres east to west, enclosed by a bank between 3.4 and 6 metres wide. That regularity, even in its diminished state, is what distinguishes it from the surrounding landscape.

This is a univallate rath, meaning a ringfort enclosed by a single earthen bank rather than the two or three concentric rings found at more elaborate sites. Raths of this kind were the most common form of rural settlement in early medieval Ireland, typically serving as enclosed farmsteads for a family and their livestock. The one at Coolnaleen is recorded as being in a poor state of preservation, its bank reduced and fragmented. One detail adds a small puzzle: extending from the south-south-east sector of the bank is a low, straight earthwork running eastward, which may represent the remains of an earlier field boundary. Whether it predates the rath, postdates it, or was simply absorbed into its layout is not clear. C. Toal documented the site in the North Kerry Archaeological Survey, published in 1995, which remains the primary record of what survives here.