This one in the townland of Mortgage, County Limerick, offers none of that. It exists, at least to human eyes at ground level, as a complete absence, a circular enclosure that has left no earthwork, no upstanding feature, and no surface trace whatsoever. What remains is a ghost written in grass, legible only from above and only under the right conditions.

The site was never recorded on the Ordnance Survey's 6-inch map of 1840, nor on the more detailed 25-inch edition of 1897, which suggests it had already vanished from the landscape long before systematic mapping began. Its existence came to light in 1986, when aerial photographs taken during survey work for the Curraleigh to Limerick gas pipeline revealed a circular cropmark in the low-lying, gently undulating pasture. Cropmarks form when buried features, such as the ditches or banks of an ancient enclosure, affect how the vegetation above them grows; a filled-in ditch retains more moisture and produces lusher, darker growth, while a buried wall does the opposite. The circular form suggests a ring enclosure of the kind common across early medieval Ireland, used as farmsteads or settlement boundaries, though no excavation has confirmed a date or function here. A barrow, a burial mound of likely prehistoric origin, lies around 220 metres to the north-west, hinting that this quiet corner of Limerick was more densely occupied in the distant past than the blank fields now suggest. When the Archaeological Survey of Ireland visited in 2000, they found nothing visible at ground level. Subsequent aerial imagery told a more flickering story: a partial cropmark appeared on an Ordnance Survey Ireland orthophoto taken between 2005 and 2012, and a faint circular outline showed again on a DigitalGlobe image from 2011 to 2013, before disappearing entirely from a Google Earth image captured in June 2018.

There is little to direct a visitor here in any conventional sense. The site sits in ordinary farmland, and without the elevated perspective and the precise atmospheric conditions that make cropmarks legible, there is nothing to see. What makes it worth knowing about is precisely that instability: a site that flickers in and out of visibility depending on rainfall, season, and the angle of a satellite. The best chance of glimpsing it, should aerial imagery ever be updated for the area, would be during a dry summer spell, when moisture stress in the soil above buried features tends to sharpen the contrast. The surrounding landscape is low and open, the kind of ground where, once you know to look, you start to wonder what else is written underneath.