Dublin is a county in Ireland. It is sometimes officially referred to as the Dublin Region and is in the province of Leinster. It is named after the city of Dublin, which is the regional capital and the capital city of Ireland. County Dublin was one of the first parts of Ireland to be shired by King John of England following the Norman invasion of Ireland.

Prior to 1994 County Dublin was an administrative county run by a county council with functional area covering the whole county excluding the functional area of Dublin City Council. In 1994 Dublin County Council was abolished and replaced with three separate administrative county councils: Dún Laoghaire–Rathdown, Fingaland South Dublin.

The population of the county was 1,270,603 according to the census of 2011.