Set on a break in a south-facing slope, in ordinary pastureland, is an enclosure roughly 36 metres across, its outline still traceable but only just. The bank that defines it rises less than half a metre above the interior ground level, and cattle working the eastern side have worn it down further still. Along the southern edge, the bank has been reduced to little more than a scarp, and the shallow external fosse, a defensive ditch running around the outside, is barely legible in the ground.

Enclosures of this kind are among the most common archaeological features in the Irish landscape, typically associated with early medieval settlement and farming, the ancestors of the more familiar ringfort. What makes the Clonalea example quietly interesting is a small discrepancy: the shape recorded on the ground does not quite match what the first edition Ordnance Survey six-inch map, produced in the nineteenth century, shows for the same spot. Three sides, the north, west, and south, run in notably straight lines, giving the enclosure an irregular rather than circular form. Whether that irregularity reflects the original design, later disturbance, or gradual erosion across centuries of agricultural use is not clear. The site measures approximately 36 metres north to south and 35.5 metres east to west, dimensions that fall within the typical range for a small enclosed settlement, but the straightened sides set it slightly apart from the rounded norm.