This circular earthwork, measuring 36 metres from northeast to southwest and 32 metres from northwest to southeast, represents a type of fortification favoured by the Anglo-Normans during their initial conquest of Ireland in the late 12th and early 13th centuries.

The site consists of two concentric earth and stone banks with a substantial defensive ditch, or fosse, running between them. The inner bank, which stands about 4 metres wide and rises over 3 metres on its outer face, still shows traces of stone wall footings along its top; evidence of the defensive structures that once crowned these earthworks. The outer bank, somewhat smaller at 2 to 3 metres wide, has suffered damage over the centuries, particularly along its northern and eastern sections. Between these two rings runs a flat-bottomed ditch approximately 4 metres wide, which would have presented a formidable obstacle to any attacking force.

Two original entranceways break through the defences; a 3.5-metre-wide causeway on the northeast side and a narrower 2.5-metre passage to the southeast. These causeways, which allowed controlled access across the defensive ditch, would have been the castle’s most vulnerable points and likely featured additional defensive works such as gates or drawbridges. The positioning of this ringwork on elevated ground with a southern aspect would have provided its occupants with excellent views over the surrounding countryside, allowing them to monitor and control movement through this part of medieval Tipperary.