The monument consists of a 28-metre diameter enclosure surrounded by a stone-built bank and an external ditch, or fosse. The bank, now covered in earth and moss, stands between 0.3 and 1.5 metres high, though it’s clear that stone has been removed from several sections over the centuries. The surrounding ditch maintains a consistent width of about 2.45 metres and depth of 0.7 metres, with a notably flat bottom that runs uniformly around the enclosure, except for a 4-metre gap in the south-southeast where a dip in the bank suggests this may have been the original entrance.

The interior of the enclosure slopes downward towards the south and has an uneven surface, bisected by a low field boundary bank running north to south. This later addition, along with the monument’s position cutting into an adjacent henge (archaeological site LI013-089), tells us something about how the landscape has been reused and modified over time. The construction technique, using loose stonework covered with earth, is typical of medieval defensive structures in Ireland.

Whilst initially recorded as a simple enclosure, researchers Kelly and Condit suggested in 1998 that this monument might actually be a ringwork; a type of medieval castle consisting of a circular or oval defensive bank and ditch, typically dating from the Norman period in Ireland. These earthwork castles were often quickly constructed to secure newly conquered territories and could be topped with wooden palisades and buildings. The presence of what appears to be a single entrance and the substantial defensive earthworks certainly support this interpretation, making this site at Friarstown North an important piece of Limerick’s medieval heritage.