It measures roughly 26 metres across and stands about 2.5 metres high, which is modest enough that a casual observer might take it for a natural feature. What makes it quietly odd is what happened to its eastern side: at some point someone quarried into it, cutting away a section and exposing a gravelly core. That excavated hollow has since been filled in with field clearance, the accumulated stones and debris of working farmland, so the mound now carries evidence of two separate human interventions separated by an unknown span of time.

The site sits in a part of Galway where earthworks of various periods are not uncommon. Circular mounds in Irish landscapes can represent a range of origins, from burial cairns and ring barrows of the Bronze Age to the raised platforms of ring forts, known as raths, which served as enclosed farmsteads through the early medieval period. Without excavation it is rarely possible to say which a given mound represents, and this one at Gortnagoyne is no exception. What the quarrying revealed, a gravelly rather than earthen interior, slightly complicates a straightforward reading. A small stone-built hut of relatively recent construction abuts the mound on its southern side, and tree stumps are piled around the perimeter, suggesting the site has been put to various informal uses over the years even as its original purpose has been forgotten.