Slieve Croob is a mountain with a height of 534 metres in the middle of County Down, Northern Ireland. It is the heart of a mountainous area, the Dromara Hills, north of the Mourne Mountains. It is designated an Area of Outstanding Natural Beauty and is the source of the River Lagan. There is a small road to the summit, where there is an ancient burial cairn and several transmitter stations with radio masts. It has wide views over all of County Down and further afield.