It is the kind of early medieval ecclesiastical enclosure, a broadly circular boundary marking sacred and monastic space, that once defined communities of early Irish Christianity, and this one has been eroded, ploughed, waterlogged, and absorbed into the landscape over more than a thousand years. Parts of it remain as a broad, flat bank with a deep, flat-bottomed fosse, the term for a defensive or boundary ditch, beside it; other stretches survive as nothing more than a ledge cut into the slope of a ridge, or as a large hollow along a field edge. To the north and north-east, where the ground is low-lying and wet, nothing is visible at all above the surface.

Excavations carried out in 2005 and 2006 began to recover what the ground had swallowed. The 2005 work showed that the northern quadrant had once been defined by both an internal and an external fosse, with a bank between them, though the bank itself had long since been levelled by ploughing. The following year, excavation of the north-eastern limit revealed something older and more striking: a substantial timber palisade, a fence of upright wooden stakes forming a boundary, accompanied by an external stream. Radiocarbon dating placed the construction of this palisade in the late seventh to the first half of the eighth century. That date is significant, because it corresponds closely to the lifetime of Beccán, the founder associated with this site, who died in 689. The palisade appears to have been built during or very shortly after his lifetime, making it among the earliest datable structural evidence for the community he founded. Peakaun's stream, which still runs roughly north to south through the interior of what was once the enclosure, may itself have served as part of the eastern boundary in that earlier phase.