What survives is a concentric enclosure, a form of monument in which two roughly circular earthen banks are thrown up one inside the other, separated by a wide open space. The inner subcircular area measures roughly 34 metres north to south and 32 metres east to west, while the total span of the whole structure, outer bank included, runs to about 65 metres. Between the two banks lies a berm, that open interval of ground, approximately 10 metres wide, and outside the inner bank there is still a slight fosse, meaning a shallow ditched depression. A gap of about 1.8 metres in the inner bank on the north-east side marks what was the original entrance.

Concentric enclosures are relatively rare in the Irish landscape and their function remains a matter of some debate among archaeologists. They may represent high-status ringfort variants, places of assembly, or sites with a ceremonial dimension that went beyond simple domestic enclosure. The double-bank arrangement, with its broad berm, suggests a degree of elaboration and effort that sets such sites apart from the more common single-banked ringfort. At Froghanstown, the outer bank has been considerably reduced, levelled along its south-south-west to north and north-east arc, and a later field fence running roughly north to south cuts across the western side of the site, so the monument now reads as a partial outline rather than a complete circuit. Bishop's Lough lies just 220 metres to the north-east, and the elevated position of the site, modest as the rise is, gives long views across the surrounding undulating midlands countryside, a quality that may well have been as deliberate a choice in antiquity as it appears today.