Dún Laoghaire–Rathdown is a county in Ireland. It is part of the Dublin Region in the province of Leinster. It is named after the former borough of Dún Laoghaire and the barony of Rathdown. Dún Laoghaire-Rathdown County Council is the local authority for the county. The population of the county is 206,261 according to the 2011 census.

Dún Laoghaire-Rathdown County Council is the authority responsible for local government in the county of Dún Laoghaire–Rathdown, Ireland. It is one of three local authorities that comprised the former Dublin County Council before its abolition and one of four councils in the Dublin Region. As a county council, it is governed by the Local Government Act 2001. The council is responsible for housing and community, roads and transportation, urban planning and development, amenity and culture, and environment. The council has 40 elected members. Elections are held every five years and are by single transferable vote. The head of the council has the title of Cathaoirleach (Chairperson). The county administration is headed by a Chief Executive, Philomena Poole. The county town is Dún Laoghaire. It serves a population of approximately 206,260.