The earthworks at Glenlara are modest by any measure, a roughly circular enclosure just over twenty-two metres across, but the presence of a souterrain in its interior lifts it out of the ordinary. A souterrain is an underground stone-built passage or chamber, typically associated with early medieval ringforts and used variously for storage, refuge, or concealment. Their construction required real effort and intent, and their survival alongside the surface earthworks makes a site like this one considerably more than a simple field boundary.

Ringforts, known in Irish as raths when they are earthen rather than stone-built, were the dominant settlement form in early medieval Ireland, roughly from the fifth to the twelfth century. Thousands survive across the country in various states of preservation. The Glenlara example follows a familiar pattern: a slightly raised interior platform enclosed first by an inner earthen bank, then a fosse (a ditch dug to provide material for the bank), then an outer bank, with a further shallow external fosse to the north-west. The inner bank survives to only about thirty centimetres in height, the outer to a maximum of seventy centimetres, which suggests either original modesty or gradual erosion through centuries of agricultural use. The site sits on a gentle west-facing slope in land that is still used for grazing, a continuity of purpose, if not of inhabitant, that would not have seemed strange to whoever once lived here.

The interior is overgrown with reeds, which can make the ground conditions soft underfoot and the earthworks harder to read at close quarters. The grass-covered banks are easier to trace from a slight distance, where the double-bank and fosse arrangement becomes more apparent as a series of low concentric ridges. The souterrain recorded within the enclosure is catalogued separately, and its exact condition and accessibility are not documented here, but its presence is worth bearing in mind when reading the ground surface.