The feature is subcircular in shape, roughly 26 metres from north to south and 23 metres from east to west, and it sits in a large open field at Castlefergus, unremarked by any roadside sign.

Enclosures of this kind, defined by a raised bank rather than a ditch or wall, appear throughout the Irish countryside in considerable numbers and belong to a broad category of earthwork that could date from the early medieval period or earlier. They are often associated with habitation, with the enclosing bank serving to mark and protect a domestic space, though some were used for agricultural or ceremonial purposes. Without excavation it is rarely possible to say with confidence which function any particular example served. At Castlefergus, the bank is modest enough that it reads more as a ripple in the field than a deliberate structure, which is part of what makes such features easy to overlook and, when noticed, quietly arresting. The site sits within the broader landscape of the River Rine, a tributary that drains much of east Clare before meeting the Shannon estuary system to the south.