What distinguishes it, to the trained eye, is its almost perfect circularity and the curious completeness of its enclosing bank, a low broad earthen rim with no visible break, no entrance, and no surrounding ditch. Most earthworks of this kind are accompanied by a fosse, the trench from which material was dug to build the bank, but here the ground is unbroken on all sides, lending the whole thing an unusually sealed, self-contained quality.

An embanked barrow is a burial mound of prehistoric date, typically consisting of a raised central area enclosed by a low earthen bank, sometimes with a ditch between the two. The example at Castlegal is modest in scale, the raised interior measuring roughly fourteen metres east to west and thirteen metres north to south, with the bank itself some six metres wide and only about fifteen centimetres high at its interior face. That uniformity of profile is itself notable. The bank shows no sign of collapse, disturbance, or a gap that might indicate where people once entered or exited the enclosed space, which raises quiet questions about how the site was used and by whom. Without excavation, what lies beneath the slightly raised ground at its centre remains unknown.