Roughly 35 metres across in both directions, it is broadly square with rounded corners, yet the earliest Ordnance Survey map to record it, dated 1846, shows it as a circle. By 1894 a revised survey had settled on something closer to a square, with a gently curving western side. The earthen bank that defines it stands over two and a half metres high on its exterior face, though it has dropped to almost nothing on the interior, and it is broken in numerous places by gaps. Large boulders sit along the eastern and north-western sections of the bank, most likely gathered there during centuries of field clearance rather than as any original feature of the structure.

This is almost certainly the site recorded in the 1840s under the name 'Maistorgluishy Fort', noted at that time as lying on the south-western side of the townland of Mastergeeha, in the parish of Kilcummin. Enclosures of this kind, sometimes called ringforts or raths, were typically built in early medieval Ireland as enclosed farmsteads, the bank and its original accompanying ditch serving to define a domestic space and keep livestock secure. What makes this one quietly puzzling is the long documentary disagreement over its form. The shift from circular to square between the two Ordnance Survey readings is not simply a matter of cartographic refinement; aerial photographs taken in 1977 confirm the square shape with rounded corners that the later map suggested, raising the question of whether the 1846 surveyor genuinely saw something different, or simply defaulted to the more familiar circular outline when sketching what was already a worn and gapped earthwork.