Dún Laoghaire is a suburban coastal town in County Dublin in Ireland. It is the administrative centre of the county of Dún Laoghaire–Rathdown. The town was built up alongside a small existing settlement following 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 from which "Dunleary" was anglicised. Over time, the town became a residential location, a seaside resort, the terminus of Ireland's first railway and the administrative centre of the former borough of Dún Laoghaire, and from 1994, of the county of Dún Laoghaire–Rathdown.

County Dublin is a county in Ireland, and holds its capital city, Dublin. It is located on the island's east coast, within the province of Leinster. Until 1994, County Dublin was a single local government area; in that year, the county council was divided into three new administrative counties: Dún Laoghaire–Rathdown, Fingal and South Dublin. The three administrative counties together with Dublin City proper form a NUTS III statistical region of Ireland. County Dublin remains a single administrative unit for the purposes of the courts and Dublin County combined with Dublin City forms the Judicial County of Dublin, including Dublin Circuit Court, the Dublin County Registrar and the Dublin Metropolitan District Court). Dublin also sees law enforcement and fire services administered county-wide.