No earthwork rises from the ground in any obvious way; instead, the enclosure betrays itself only from the air, where the buried outlines of a bank and an external fosse, a defensive ditch ringing the outer edge, show up as a cropmark, a phenomenon where buried features affect how overlying vegetation grows, leaving faint but readable traces in dry summers when crops or grasses are stressed.

The site came to light through an aerial photograph taken on 18 July 1970, part of the Cambridge University Collection of Aerial Photography. What it captured was a circular enclosure roughly 40 metres in diameter, the classic form of an early medieval rath, a type of enclosed farmstead used across Ireland broadly between the fifth and twelfth centuries. Raths were typically the home of a farming family of some social standing, the bank and fosse serving as much as a marker of status and a means of managing livestock as a defensive structure. At Castlehyde, the fosse appears to run outside the bank, a standard arrangement, and the overall scale is consistent with a modest, single-family enclosure rather than one of the more elaborate multivallate sites reserved for higher-ranking individuals.

The cropmark format means there is likely little or nothing visible at ground level today, and the site is most meaningful as a reminder of how densely settled the Irish countryside once was, and how much of that settlement has quietly dissolved back into the soil.