County Down, (Irish: Contae an Dúin, meaning County of the Fort. Ulster Scots: Coontie Doun.) is one of the nine counties that form the province of Ulster and one of six counties that form Northern Ireland. The county forms an area of 2,448 km2(945 sq mi).The county borders County Antrim to the north, the Irish Sea to the east and County Armagh to the west