A rectangular embanked enclosure, roughly 35 to 40 metres along its longer axis, was recorded on the first Ordnance Survey mapping of the area in 1837 and was still traceable on the third-edition six-inch OS map produced in 1930, by which point it had been partially absorbed into a field boundary along its northern side. By the early 1990s, land reclamation had levelled it entirely. No earthworks, no banks, no surface trace remains.

The enclosure sat on a low north-to-south ridge, positioned at the break of slope on the western side, the kind of placement that suggests deliberate siting for drainage or outlook rather than accident of convenience. Its relationship to the wider landscape is quietly interesting: approximately 250 metres to the west, on a parallel ridge, sits a rath, a type of circular earthen enclosure associated with early medieval settlement and farming. Raths were typically used as enclosed farmsteads, and their presence across the Irish countryside in the hundreds of thousands speaks to a dense pattern of early rural life. Whether the rectangular enclosure at Knockegan and Cloonagh Beg was contemporary with, earlier than, or later than that neighbouring rath is not recorded. What is clear is that the two features occupied similar ground, with similar orientations toward what modest views the low ridge could offer, while higher ground to the north-east looked down over both of them.

There is nothing to see here now, which is itself the point. The 1837 mapping and the 1930 revision together preserved a record of something that local land improvement subsequently erased. The enclosure's dimensions, its alignment, its position on the slope, all of it survives only in cartographic form, a set of lines on old paper describing a shape that the ground no longer holds.