Field systems, as archaeologists call them, are the fossilised layouts of early farms: the banks, ditches, walls, and boundaries that once divided ground for cultivation or grazing. They survive in Ireland in remarkable numbers, many of them invisible at ground level but legible from the air or through careful walking of the terrain. The one recorded at Killogilleen is among the quieter entries in the national monuments record, noted and mapped but not yet widely written about.

Field systems in Ireland range in date from the Neolithic through to the post-medieval period, and without detailed excavation or survey it is rarely possible to assign a confident date to any individual example. Some of the most dramatic survivals, such as the Céide Fields in County Mayo, preserved beneath blanket bog, date back more than five thousand years. Others are the remnants of the ridge-and-furrow cultivation that intensified in the medieval period, or the small enclosed plots associated with pre-Famine tenant farming. The Killogilleen system falls somewhere within that long continuum. The townland name itself, derived from the Irish, hints at an ecclesiastical association, though the field boundaries belong to a separate, agricultural layer of the landscape's history.