It cannot be seen by walking the land. It only reveals itself from above, and only under the right conditions, when moisture or crop stress draws the hidden geometry to the surface as a pattern of perpendicular cropmarks forming what surveyors describe as a grid-iron arrangement. Whatever made these lines, they were pressed into the ground deeply enough that the earth still remembers them.

The site sits in pasture just west of the townland boundary with Ballygrennan, roughly 580 metres northeast of Greenpark House. A separate enclosure, recorded in the Sites and Monuments Register as LI040-004, occupies the western quadrant of the field system, suggesting at least two phases or elements to what lies underground. The feature was first noted on an aerial photograph taken on 11 September 1982 during survey work for the Bórd Gáis Éireann Curraleigh West-Limerick gas pipeline, a project that inadvertently produced some of the most useful aerial archaeology of the Irish midlands and west. The grid-iron pattern reappeared on Ordnance Survey orthophotography taken between 2005 and 2012, and was clearly legible again on Digital Globe imagery from 2011 to 2013. On various Google Earth images the linear cropmarks, which are the faint discolouration in growing crops or grass caused by buried features affecting soil drainage or nutrient levels, show up as waterlogged channels, implying that whatever lies beneath holds or sheds water differently from the surrounding pasture. The compilers of the record note that these linear features may represent drainage channels associated with reclamation and landscaping works connected to Greenpark House, rather than anything older, though that question remains open.

This is not a site with a car park or an information board. It lies on private farmland and is not accessible to visitors in any conventional sense. Its interest is largely one of method: a place that exists, at present, only as a pattern on a screen or in an archive photograph, waiting for the conditions, a dry summer, a particular crop, a low sun angle, that might one day make it legible again from the air. Anyone with an interest in aerial archaeology would find the 1982 BGE survey photograph a worthwhile starting point, held as part of the pipeline survey record referenced as BGE 1/5000, 2540. The record was compiled by Fiona Rooney and uploaded to the national monuments database in May 2021.