What makes it worth pausing over is a small puzzle at its south-east side: a gap just 1.2 metres wide that researchers suspect is not the original entrance at all, meaning the true way in has either been obscured or simply lost to time.

This kind of enclosure is known as a ringfort, a form of enclosed farmstead that was the dominant settlement type in early medieval Ireland, roughly from the fifth to the twelfth century. The term cashel, used in the site's classification, refers specifically to a ringfort defined by a stone wall rather than an earthen bank, distinguishing it from a rath, which relies on raised earth and ditches. The distinction matters here because the bank at Rathshanmore is stone-faced, giving it that cashel character, though Reynolds, writing in 1973, catalogued it simply as a small rath. The enclosure measures approximately 29.5 metres north to south and 31.4 metres east to west, making it modest in scale. The wall stands noticeably higher on the eastern exterior, reaching 1.4 metres, than on the western side, where the exterior face is only 0.25 metres above the surrounding ground. This asymmetry is almost certainly a consequence of the sloping terrain rather than deliberate design, the hillside itself shaping how much of the structure remains visible from different angles.