In a field somewhere in the Kildare townland of Ballysaxhills, there is an enclosure that most people will never see, at least not from the ground. It exists, to all practical purposes, only from the air, as a cropmark: a ghostly circular outline pressed into the vegetation by a buried fosse, which is the ditch that would once have defined the outer boundary of a small enclosed space. The fosse itself has long since silted and settled, but the differential growth of crops above it betrays its presence when conditions are right, the kind of quiet persistence that aerial photography occasionally catches.

The enclosure was recorded in a 1969 aerial photograph, in which its circular fosse appears clearly enough to estimate a maximum diameter of around 25 metres. That is a modest size, roughly comparable to a small ringfort, the type of enclosed farmstead that was common across Ireland during the early medieval period. Whether this particular enclosure belongs to that tradition, or to something earlier or later, the available evidence does not say. What it does confirm is the outline of a deliberately enclosed circular area, defined by a ditch and preserved, improbably, in the pattern of a crop photographed over half a century ago.