A line of trees crowns the bank, which rises 2.2 metres above the surrounding ground. From within, that same bank drops only 1.1 metres to the level interior, a detail that gives some sense of how the structure was designed to present an imposing face outward while keeping its interior relatively accessible to those who belonged there.

The rath is a univallate example, meaning it has a single enclosing bank rather than the multiple concentric rings that mark higher-status sites. Ringforts of this type were the most common form of rural settlement in early medieval Ireland, typically enclosing the farmstead of a single family or small household between roughly the fifth and twelfth centuries. What makes Lios An Tsionnaigh a little more distinctive is the care taken with its construction. The bank, though largely earthen in its core, is faced with drystone masonry on both its inner and outer surfaces, giving it a more finished and deliberate character than a simple earthen ringfort would suggest. The bank has a basal width of 4.2 metres, and a gap of 1.6 metres in the north-east may preserve the original entrance, oriented in a direction commonly favoured at such sites. The interior, roughly 21 metres across on its north-south axis and 20 metres east to west, appears featureless at ground level, though that absence of visible remains says little about what may lie beneath the surface.

The fort sits a short distance south of the Inny river, close to the valley head, in a landscape that still feels relatively remote. The setting on a small natural hillock would have given its original occupants a modest but real advantage in terms of visibility and drainage, both practical concerns for anyone building a permanent enclosure in this part of Kerry.