Slieve Binnian (from Irish: Sliabh Binneáin, meaning 'mountain of the little peaks') is one of the Mourne Mountains in County Down, Northern Ireland, 9 km north of Kilkeel. It is the third-highest mountain in Northern Ireland at 747 metres (2,451 ft). The summit is broad and flat with rocky tors at the north and south ends, with the Back Castles, impressive towers of granite, in between. To the south-west is Wee Binnian (from Irish: Broinn Bhinneáin, meaning 'breast of Binneán') (460m). It lies east of Silent Valley Reservoir and west of the Annalong Valley. The Mourne Wall also crosses over Slieve Binnian.