On a gentle slope in the foothills of the Comeragh Mountains, there is a low swelling in the grass that most walkers would pass without a second glance. It is slightly raised, subtly oval rather than perfectly round, and measures roughly 34 metres across its longer axis. The boundary is not a wall or a ditch but a scarp, a low step in the ground no more than about 30 centimetres high, giving the whole thing the quality of something half-remembered rather than clearly stated.

Enclosures of this kind are among the more quietly enigmatic features of the Irish landscape. Circular or subcircular enclosures, sometimes called ringforts or raths depending on their form and probable function, were used throughout early medieval Ireland for settlement, agriculture, and possibly ritual purposes, though many remain undated without excavation. This particular example at Boolabeg was already recorded on the Ordnance Survey's six-inch map of 1840, suggesting it was sufficiently visible at that point to catch a surveyor's attention. What makes it slightly unusual is the absence of any visible fosse, the term for the external ditch that typically accompanies such enclosures, and the lack of any discernible entrance. Without these features, its original character and purpose are difficult to read from the surface alone. The Douglas River runs roughly 120 metres to the south-east, a modest but consistent detail; water access was a practical consideration for most forms of early settlement and enclosure.