Only from the air does its shape emerge: a large trapezoidal enclosure, roughly 30 metres north to south and up to 65 metres east to west at its broader northern end, tapering as it runs south. What gives it away is a cropmark, the faint differential in how grass or grain grows over buried features, in this case the filled-in ditches, or fosses, that once defined the enclosure's boundaries. A second outer fosse is also traceable on the eastern, southern, western, and part of the northern sides, suggesting this was a place that somebody once felt worth enclosing twice.

The enclosure came to light through aerial photography carried out in July 1989 as part of the Cork Aerial Survey and Archaeological Project. Its trapezoidal form is notably unusual. The more familiar enclosed sites of early medieval Ireland tend toward the circular, the classic ringfort being a single or occasionally double-ditched circular enclosure used as a farmstead. Rectilinear or trapezoidal enclosures exist but are far less common, and their functions are not always straightforward to interpret. What makes the Ballymee site particularly interesting is its immediate neighbourhood. A ringfort sits roughly 40 metres to the northeast, two further circular enclosures lie within 200 metres to the east and north-northeast, and a field system has been recorded in the general vicinity. This clustering hints at a landscape that was, at some point, densely organised and actively used, with the trapezoidal enclosure perhaps playing a different functional role from its circular neighbours, whether administrative, agricultural, or something else entirely.