Roughly fifteen metres in diameter, it exists now only as a so-called shadow site, a category of archaeological feature that becomes legible only from the air, when variations in soil moisture, crop growth, or grass colour briefly betray what lies beneath. The enclosure at Knockreer falls into this quietly eerie class of place: present, technically, but invisible to anyone standing on it.

The enclosure came to light in an aerial photograph taken in 1956, which captured the slight tonal difference in the vegetation on a gentle south-facing slope, enough to reveal the circular outline beneath. A rectangular enclosure of related or at least neighbouring interest sits around ten metres to the south. Circular enclosures of this kind are frequently associated with early medieval settlement in Ireland, often the remains of a ringfort or domestic enclosure, though the notes here are careful not to specify a date or function beyond what the aerial evidence alone can confirm. The south-facing slope would have made it an attractive location for habitation, offering shelter and light, and the Knockreer area sits within a landscape that has seen continuous human activity across many centuries.