Rathdown School, an all-girls institution founded in 1973, incorporates four original schools: The Hall, Hillcourt, Glengara Park and Park House. The amalgamation of Rathdown is comprised of a junior school and a senior school with a boarding department. Currently the junior school has 189 pupils, while the senior school has 312 students, 109 of whom are boarders.​ Rathdown operates under Protestant Management, is owned by Rathdown School Trust, a registered charity, and is limited by guarantee.

​

The School is located on a 16-acre site on Upper Glenageary Road overlooking Dun Laoghaire and Dublin Bay. The two main houses, Hillcourt, (the boarding house) and Tudor (the Principal’s residence), date from the early nineteenth century. The grounds are maintained to a very high standard, creating an environment of beauty and tranquillity. The school buildings constantly are being improved and updated. The present senior school dates back to 1994, with a further extension opened in 1998. The Junior School was extended and the Principal’s house was refurbished five years later. In 2005, a new building opened housing single-bed rooms on three separate floors for senior students. ‘Innismore’ also includes state-of-the-art music facilities and an auditorium on the ground floor.