Man-made underground passage in Irishtown (duleek Upper By., Moorechurch Par.)

No visible mound or stone remains, only a faint shadow in the soil beneath the grass. The trench stretches twenty-three metres east-west before bending north at its widest point, suggesting a deliberate entrance rather than a random crack. It lies inside the defensive ditch of an ancient rath, hidden from ordinary sight but captured by a modern satellite survey. Perhaps people once walked beneath the town, using the passage to move unseen through land they believed belonged to others.