Down is one of six counties that form Northern Ireland, situated in the north-east of the island of Ireland. Adjoined to the south-east shore of Lough Neagh, the county covers an area of 2,448 km² and has a population of about 531,665. It is also one of the thirty-two traditional counties of Ireland and is within the province of Ulster.
The county was archaically called Downshire. It borders County Antrim to the north, the Irish Sea to the east and south, County Armagh to the west, and County Louth to the southwest. In the east of the county is Strangford Lough and the Ards Peninsula. The largest town is Bangor, on the northeast coast. Three other large towns and cities are on its border: Newry lies on the western border with County Armagh, while Lisburn and Belfast lie on the northern border with County Antrim. Down contains both the southernmost point of Northern Ireland (Cranfield Point) and the easternmost point of Ireland (Burr Point).
It is currently one of only two counties of Ireland to have a majority of the population from a Protestant community background, according to the 2001 census. The other is County Antrim.