On the ground, it has vanished entirely into improved pasture. No ordnance survey map, historic or modern, ever recorded it. A satellite image from 2018 shows nothing at all. Yet for a brief window, under the right conditions of crop growth and summer light, an aircraft passing over the townland of Knockballyfookeen captured the ghost of a roughly circular enclosure pressed into the soil beneath the fields.

The monument was identified during the Bruff aerial photographic survey of 1986, appearing as a cropmark, specifically reference Bruff 270, AP 4/3677. Cropmarks form when buried features, ditches, walls, or banks, affect the moisture available to the crops or grasses growing above them. Filled ditches retain more water and produce lusher, darker growth; buried stonework does the opposite. The circular outline that showed up in 1986 was almost certainly the remnant of a ditch defining an enclosed area, the kind of feature associated in Irish archaeology with early settlement, agricultural use, or ritual. The enclosure sits in low-lying, heavily drained land, cut through by watercourses, just ten metres east of the townland boundary with Ballyhurst. Two related monuments lie close by, a ditch-barrow approximately 85 metres to the southeast and a second enclosure around 110 metres to the southwest, suggesting this corner of Limerick was once a more structured landscape than its current appearance would suggest. The record was compiled by Alison McQueen and Vera Rahilly and uploaded in October 2020.

There is, frankly, nothing to see at Knockballyfookeen if you go looking. The orthophotography from 2005 to 2012 shows no trace, and a Google Earth image from November 2018 is equally blank. The land has been improved, drained, and worked to a point where the enclosure survives only as data, a reference number in the National Monuments database and a frame in a forty-year-old aerial survey. That is not unusual for this type of site; many of Ireland's most significant early enclosures are known only through aerial reconnaissance and have never been excavated or even precisely located on the surface. The value of Knockballyfookeen lies less in what a visitor might find and more in what the 1986 photograph quietly confirms: that the fields here have a depth of history entirely invisible at eye level.