What gives it away, to anyone who knows what to look for, is the subtle geometry: a diameter of just over forty metres, an enclosing earthen bank, and the shallow depression of an outer fosse running around it. A fosse, in this context, is simply a defensive ditch dug to reinforce the bank that was raised from the same spoil, a common feature of early Irish ringforts.

The entrance, at the south-east, is narrow at its base, measuring around two and a half metres across, and there is no causeway bridging the fosse at that point, which is itself a small curiosity. Many comparable enclosures have a raised crossing at the entrance, allowing animals or carts to pass over the ditch; its absence here may reflect the site's particular history or simply the degree to which the earthwork has silted and settled over centuries. Along the north-east to east arc of the fosse, a field bank runs close to the outer edge, skirting the enclosure in a NW-SE alignment. Whether this boundary is contemporary with the fort or was added later as farmland was divided around it, the two features now sit in a quiet conversation across the landscape of the spur.

The fort sits on a small north-east to south-west ridge, which would have given whoever occupied or built it a modest but real advantage in terms of visibility and drainage. These earthen ringforts, of which thousands survive across Ireland to varying degrees of preservation, were typically built during the early medieval period, roughly between the fifth and twelfth centuries, and served as enclosed farmsteads or seats of local power rather than purely military strongholds. At Garrybane, the enclosure is overgrown but largely intact, its bank and fosse still legible in the ground despite the scrub that has claimed much of the interior.