Ringhaddy (from Irish Rinn an Chadaigh 'point of the covenant'[1]) is a townland on the shores of Strangford Lough, County Down, Northern Ireland, 5 km south of Whiterock.

In 1470 the castle was recorded captured by Henry O'Neill, then transferred to MacQuillen of Dufferin.

[3] A c.1580 map of County Down showed Renaghaddye, with 2 castles and a church, on a peninsula or island.

The area has become very popular for diving, with the wreck of the MY Alastor some 80m offshore from Ringhaddy Quay at a depth of 23m.

This 143 ft luxury motor yacht was built in 1927 and destroyed by fire on 11 March 1946 while moored up for painting.