Two Rock is a mountain in Dún Laoghaire–Rathdown, Ireland. It is 536 metres high and is the 382nd highest mountain in Ireland. It is the highest point of the group of hills in the Dublin Mountains which comprises Two Rock, Three Rock, Kilmashogue and Tibradden Mountains. The mountain takes its name from the two granite tors that lie to the south-east of the summit. From the summit, which is called Fairy Castle, there are views of much of the Dublin area from Tallaght to Howth to the north while Bray Head, Killiney Hill, the Great Sugar Loaf and the Wicklow Mountains are visible to the south. The summit area is mostly shallow bog while ferns and gorse cover the lower slopes. The mountain is also an important habitat for red grouse.

Dún Laoghaire–Rathdown is a county in Ireland. It is in the province of Leinster and the Eastern and Midland Region. It is one of three successor counties to County Dublin, which was disestablished in 1994. It is named after the former borough of Dún Laoghaire and the barony of Rathdown. Dún Laoghaire–Rathdown County Council is the local authority for the county. The population of the county was 233,860 at the time of the 2022 census.