First recorded on the 1837 Ordnance Survey Fair Plan map, the location was marked as a small rectangular enclosure with the tantalising annotation ‘Site of Glomerstown Castle’, suggesting the structure had already vanished by the early 19th century. The same year’s six-inch OS map depicted the area with a broken line, the cartographer’s shorthand for something no longer standing.

By 1978, when archaeologists formally surveyed the site, they found no visible surface remains of what had once stood here. The castle’s exact appearance and history remain largely mysterious, though its inclusion on early maps confirms it held enough significance to warrant documentation even after its destruction. Today, the site faces an additional layer of erasure; a railway line cuts directly through where the castle once stood, running northeast to southwest across the former stronghold.

Modern aerial photography reveals little trace of Glomerstown Castle or any associated earthworks, leaving visitors to rely on imagination and historical maps to conjure what might have been. The site stands as one of many lost Irish castles, its story preserved only in place names and cartographic memory, compiled through the careful work of researchers like Alison McQueen, Vera Rahilly and Caimin O’Brien who continue to document these ghostly landmarks.