County Dublin

County Dublin (Irish: Contae Bhaile Átha Cliath or Contae Átha Cliath) 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. Dublin is the longest-established county in Ireland, having been the first part of the island to be shired following the Norman invasion in the late 1100s.

The third smallest county by land area, Dublin is bordered by Meath to the west and north, Kildare to the west, Wicklow to the south and the Irish Sea to the east. The southern part of the county is dominated by the Dublin Mountains, which rise to around 760 metres (2,500 ft) and contain numerous valleys and forest areas, as well as several reservoirs. The county's east coast is punctuated by several bays and inlets, including Rogerstown Estuary, Broadmeadow Estuary, Baldoyle Bay and most prominently, Dublin Bay. The northern section of the county, today known as Fingal, varies enormously in character, from densely populated suburban towns of the city's commuter belt to flat, fertile plains, which are some of the country's largest horticultural and agricultural hubs.

Dublin is Ireland's most populous county, with a population of 1,458,154 as of 2022 – approximately 28% of the Republic of Ireland's total population. Dublin city is the capital and largest city of the Republic of Ireland, and the largest city on the island of Ireland. Roughly 9 out of every 10 people in County Dublin lives within Dublin city and its suburbs. Several sizeable towns that are considered separate from the city, such as Rush, Donabate and Balbriggan, are located in the far north of the county. Swords, while separated from the city by a green belt around Dublin Airport, is considered a suburban commuter town and an emerging small city.

Until 1994, the historic county was governed in two parts, the city council area and the local government area known as County Dublin. In that year, the county council area was divided into three new administrative counties: Dún Laoghaire–Rathdown, Fingal and South Dublin. The latter three administrative divisions together with the City Council area form a NUTS III statistical region of Ireland (coded IE061), and County Dublin remains a single administrative unit for the purposes of the courts (including the Dublin County Sheriff, but excluding the bailiwick of the Dublin City Sheriff) 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 (the Garda Dublin metropolitan division) and fire services (Dublin Fire Brigade) administered county-wide. Dublin retains a strong identity, and continues to be referred to as both a region and county interchangeably, including at government body level.