Dún Laoghaire is a suburban coastal town in the traditional county of Dublin in Ireland. It is the county town of Dún Laoghaire–Rathdown, one of the three authorities that replaced the old Dublin County Council.
The town was built following the 1816 legislation that allowed the building of a major port to serve Dublin. It was known as Dunleary until it was renamed Kingstown in honour of King George IV's 1821 visit, and in 1920 was given its present name, the original Irish form of Dunleary. Over time, the town became a residential location, a seaside resort and the terminus of Ireland's first railway.