Coordinates: 55°10′55″N 6°43′16″W / 55.182°N 6.721°W
Dominican College Portstewart (Irish: An Coláiste Doiminiceach, Port Stíobhaird, locally known as DCP) is a grammar school in Portstewart, County Londonderry, Northern Ireland. It is situated on a cliff overlooking the Atlantic Ocean with views over Portstewart's promenade, the northern coastline of Northern Ireland and the County Donegal hills in the Republic of Ireland.
Rock Castle was originally built by Henry O'Hara in 1834. The castle was extended in 1844 and then passed to the Crombie family before being sold to the Dominican Sisters in 1917. The Dominican College "is concerned not merely with imparting knowledge and skills, which have their place, but, more importantly with training pupils to think, to evaluate and to make decisions."