What remains is a rath, the Irish term for a ringfort, which was the most common type of enclosed settlement in early medieval Ireland, typically housing a farming family and their livestock within a raised bank and encircling ditch. Thousands of them survive across the country in varying states of repair, but this one at Coolderry carries the particular quiet of a place that has been both endured and diminished.

The enclosure measures 36 metres east to west, its boundary formed by an earth and stone bank that has largely subsided into a low scarp, now standing no more than 1.3 metres high. Outside the bank, an external fosse, the defensive ditch that would have reinforced the sense of enclosure, survives at roughly 2 metres wide and 1 metre deep. At the north-east, there is a gap approximately 4 metres across that may represent the original entrance, a feature common to ringforts, which were often oriented to favour morning light or ease of access from settled land below. The southern portion of the site tells a different story: quarrying has removed sections of both bank and fosse there, and taken part of the interior with it, leaving a clean edge where there should be a curve.