Rostrevor is a village and townland in County Down, Northern Ireland. It lies at the foot of Slieve Martin on the coast of Carlingford Lough, near Warrenpoint. The Kilbroney River flows through the village and Rostrevor Forest is nearby. It is within Newry, Mourne and Down District.

County Down is one of the six counties of Northern Ireland, one of the nine counties of Ulster and one of the traditional thirty-two counties of Ireland. It covers an area of 961 sq mi (2,490 km2) and has a population of 552,261. It borders County Antrim to the north, the Irish Sea to the east, County Armagh to the west, and County Louth across Carlingford Lough to the southwest.