It measures roughly twenty-one metres east to west and twenty metres north to south, and its boundary rises only about thirty centimetres above the surrounding grass. That modest swell in the earth is all that remains of a rath, the Irish term for a ringfort, the most common type of early medieval settlement found across the Irish countryside. These were typically earthen enclosures, built from roughly the fifth to the twelfth century, that surrounded a farmstead and its outbuildings, offering a degree of social definition and security to the family within.

The site at Ballyhoolahan appeared on the Ordnance Survey six-inch map of 1937, marked as a circular area enclosed by a broken line, which suggests the earthwork was already degraded or partially visible by that date. The surviving bank runs most clearly from the north-east around to the south-south-east, and again from the south back around to the north-north-west. Elsewhere the rise becomes harder to trace, absorbed into the contours of the slope and the generations of agricultural activity that have worked the land around it. At just over twenty metres across, it falls on the smaller end of the scale for ringforts, which in Ireland range from modest enclosures like this one to much larger and more elaborate examples with multiple banks and ditches.