What was once a clearly defined circular enclosure is now only partly legible, its earthen bank absorbed into the field fence system that runs from northwest to southeast. That bank still stands to a height of around 1.7 metres in places, its inner face reinforced with stone, which gives a sense of the effort that went into its original construction. To the south, a low rise in the ground is the only indication of the section that has since been levelled.

Ringforts, known in Irish as raths when they are earthen, were the most common form of rural settlement in early medieval Ireland, typically dating from roughly the fifth to the twelfth century. They served as enclosed farmsteads, the bank and any accompanying ditch providing a degree of security for people and livestock. The Boolybeg example was recorded on the Ordnance Survey six-inch map of 1842 as a circular enclosure with a diameter of approximately 24 metres, which places it at the smaller end of the scale for such sites. That it appears on the 1842 map suggests it was still reasonably visible at that point, though the subsequent integration of its bank into field boundaries is a fate shared by a great many ringforts across the Irish countryside, where agricultural need and the sheer practicality of a ready-made earthwork have conspired to disguise the original form.