On a gently south-facing slope in Bleantasour, a near-perfect grass circle sits quietly in the landscape, its origins reaching back over a thousand years. This is a rath, the Irish term for a ringfort, which was the standard form of rural settlement in early medieval Ireland, typically enclosing a farmstead within a circular earthen bank. What makes this one quietly interesting is how thoroughly it has melted back into the hillside; the defining bank is only about 0.8 metres high on the outside, and in much of its circuit it survives as little more than a gentle scarp barely a third of a metre tall. No fosse, the defensive ditch that usually accompanies such an enclosure on its outer edge, is visible here. No entrance gap survives either. What remains is essentially a smudge of ancient intention, a faint rim around an open grassy interior roughly 38 metres across.

The site was already recorded, in outline at least, by the time the Ordnance Survey produced its six-inch map of the area in 1840, where it appears as a circular enclosure with a diameter of approximately 35 metres. The slight discrepancy between that early measurement and more recent survey figures, which put it closer to 36 to 38 metres depending on the axis measured, gives a small sense of how these earthworks shift and settle over time, their edges softened by centuries of ploughing, grazing, and general agricultural pressure. A road fence running northwest to southeast has clipped the northeastern arc of the bank by about 14 metres, the most visible modern intrusion on the circuit. The enclosure sits on what surveyors describe as a plateau or shelf on the slope, a slight levelling of the ground that would have made it a practical as well as a defensible location for whoever built and lived here during the early medieval period.