Carrickmines Castle

Medieval castle ruins in Dublin, partly preserved beneath M50 motorway roundabouts after a contentious heritage dispute.

Carrickmines Castle was a medieval fortress in south County Dublin, built to defend the English Pale – the fortified zone of English control around Dublin. Its ruins lay directly in the path of the M50 motorway, sparking a fierce public controversy in 2003–2005 as archaeologists and heritage campaigners fought unsuccessfully to halt construction. Sections of the medieval walls and defensive structures were ultimately preserved within or beneath the M50 roundabouts. The Carrickmines case became a landmark example of the tension between infrastructure development and archaeological heritage in Ireland.