Local historian Ua Broin suggested in 1944 that the castle once stood where the gate lodge to the college now sits, in what’s known as Moyle Castle Park. Eighteenth-century maps appear to support this theory, placing the castle at a spot that corresponds with the modern entrance to the college buildings on the west side of Boot Road. These college buildings were formerly known as Moyle Park House, perhaps preserving the memory of the vanished fortress in their name.

Historical records offer tantalising glimpses of what once stood here. Austin Cooper, an antiquarian, documented the presence of a fortified house near Tully’s Castle, whilst Ball, writing in 1899, claimed that remnants of the structure could still be spotted amongst the modern buildings that had grown up around the site. The Urban Survey of County Dublin later confirmed these accounts, though today no trace of the castle remains visible above ground.

Despite extensive research and documentation efforts, including work compiled by Caimin O’Brien as recently as July 2023, Moyle Castle has effectively vanished from the landscape. What was once a defensive stronghold has been completely absorbed by later development, leaving only its name attached to nearby landmarks and the persistent efforts of local historians to piece together its story from maps, written accounts, and archaeological surveys.