²¹ According to a local source, the stone "...dates from the Bronze Age and is said to be the only prehistoric monument visible in Dundalk today. It has been known by a variety of names. The Book of Leinster refers to it as Lia Lingadan or ‘the stone of Lingadan’. Lingadan supposedly looked after cattle owned by Cuchulainn’s mother, Dechtene and may have provided this pillar as a scratching post for the animals. Others suggest that it marks the grave of Cuchulainn and Emer. Dealg Finn, or ’Finn’s Brooch’, is a more recent name, the theory being that it was a brooch dropped by Finn McCumhaill’s mother. This may also explain the origin of the name Dun Dealgan. The most likely explanation for its origin is that it was used as a route marker on an important ancient road called Sli Miodluachra that ran from Tara in Meath to Navan Fort in Armagh. This forerunner of the M1 would have skirted the Dun and forded the Castletown river at Toberona. Another similar stone on this route was removed when Castletown Cottages were being built a century ago."

Others say the stone marks the burial site of Cúchulainn, although most sources consider the standing stone at nearby Knockbridge as marking the hero's tragic demise.