What was once a defined circular or oval enclosure, the kind of defended farmstead that thousands of early medieval Irish families called home, has been reduced to a faint earthen bank on its eastern side and a degraded scarp around the rest of its perimeter. The overall oval measures roughly 40 metres east to west and 27 metres north to south, dimensions that suggest a modest but typical domestic enclosure.

A rath, to use the Irish term, was an earthen ringfort, usually formed by one or more circular banks and ditches thrown up around a family's dwelling, livestock enclosures, and outbuildings. They were constructed and occupied mainly between the sixth and tenth centuries, and they survive across Ireland in enormous numbers, though rarely in such eroded condition as this one. Here at Lettera, the summit position on a small rise would once have offered clear sightlines across the surrounding land, a practical advantage for anyone watching over cattle or watching out for rivals. What survives now is barely enough to read as a deliberate human construction rather than a natural rise, and a later field wall cutting through the monument at both the north-east and south-east adds further disruption to what little profile remains.