The enclosure at Derk exists, for most practical purposes, as an absence: a faint cropmark visible only in aerial orthophotos, a slightly raised oval of ground that field drains have cut through and partially erased. It is the kind of site that rewards patience with satellite imagery far more than it rewards a walk across a wet field.

The Archaeological Survey of Ireland recorded the site in 2007, describing a subtly elevated area measuring roughly 10 metres north to south and 26 metres east to west, its outline interrupted by drainage ditches running northeast to southwest. Those ditches belong to the landscape reorganisation associated with Derk House, an estate whose main building sits about 550 metres to the north, and whose land management has quietly altered the ground here over generations. What makes the location particularly striking is its relationship to the surrounding monuments. Derk townland contains a cluster of at least 14 barrows, the term for a type of prehistoric burial mound, concentrated in its southern half. The nearest of these lies just 60 metres to the southeast. Whether the enclosure is contemporary with those barrows, or belongs to a different period entirely, is not established in the available record, but the proximity is difficult to dismiss. Derk Hill itself, whose summit sits roughly 900 metres to the west and rises to 781 feet above sea level, provides a backdrop that suggests this was once a purposefully occupied and memorialised landscape.

The site is not signposted, not mapped in any conventional sense, and not easy to read from ground level. Its clearest expression comes through the OSi orthophoto series from between 2005 and 2012, and a Google Earth image dated 18 November 2018, both of which show the cropmark that betrays the buried feature. Cropmarks of this kind appear when buried ditches or raised ground affect how vegetation grows above them, making them legible from above in dry summers when grasses and crops respond differently to variations in soil moisture and depth. Anyone hoping to find the enclosure on foot should approach with realistic expectations: the land is private pasture, the feature is subtle, and the drainage works have truncated whatever defined its edges.