The surrounding field fences have been removed over time, leaving the earthwork standing somewhat exposed and isolated in open pasture, which has the odd effect of making it easier to read as an object. The enclosing bank rises to 3.6 metres, a substantial height that would have made the interior a genuinely defended space rather than a merely symbolic one.

Ringforts, known in Irish as raths when they are earthen rather than stone-built, were the standard form of rural settlement in early medieval Ireland, typically dating from roughly the sixth to the twelfth centuries. They served as enclosed farmsteads, protecting livestock and household members rather than functioning as military fortifications in any grand sense. The bank at Glanbannoo is stone-faced in parts, a detail that points to some care in its original construction, though a berm visible on the inner face of the bank is thought to result from slippage over the centuries rather than deliberate design. A gap 2.6 metres wide breaks the northern bank, most likely the original entrance point. The interior also contains a souterrain, an underground stone-lined passage or chamber typically used for storage and possibly as a place of refuge, a feature found in a significant number of Irish ringforts and which hints at the daily practical concerns of whoever lived here well over a thousand years ago.