The College is best known for its natural setting in grounds situated on a plateau approximately above the famous Antrim Coast Road at Garron Point overlooking the North Channel) and out towards Scotland. Garron Tower was built in 1850 at a cost of £4,000 as a summer residence by Frances Anne Vane, Marchioness of Londonderry. She had inherited this part of the Antrim estates from her mother, Anne Katherine MacDonnell, Countess of Antrim who married Sir Henry Vane-Tempest of County Durham. From 1899 Garron Tower was leased by Henry McNeill Ltd and opened as a hotel. In December 1914 there was a major fire, and the following year McNeill's purchased it for £8,500 and repaired the damage. The hotel closed its doors in 1939. In 1950 the buildings were acquired by Bishop Daniel Mageean for use as a boarding school for boys. The school opened in September 1951. On 1 April 2010, St MacNissi's College and two other County Antrim schools, St Aloysius' College, and St Comgall's College, amalgamated to become St Killian's College. Initially St Killian's began its operations from two sites – the former St MacNissi's College site at Garron Tower and the former St Comgall's College site in Larne. Currently the St Comgall's site has been demolished and St Killian's now operates exclusively from the Garron Tower site.
Buildings
Main building
The college has extensive grounds which stretch for a mile or so around the main building. This main school building has ~30 classrooms, gymnasium, 100 desk study-hall, dining room, kitchens, cloakrooms, first-aid room, offices. The tower and old building did once provide living accommodation for priests and a beautiful old dining-room. Many significant pieces by local artists such as Charles McAuley and Sam McLarnon hang in this old section of the school.
Chapel
The Chapel was completed in 1955 with the help of the late Fr. Charles Agnew's "Mile of Half-Crowns". On the canopy above the High Altar are the words "Laudate Pueri Dominum" which translates as "Boys, Praise the Lord". On one of the stained glass windows which were installed in late 1956, the following words, in very small print, are to be found: "As I am making this window the Hungarians have risen in revolt against Communist/Russian rule in Hungary. October 1956".
Boarding rooms
A 150-room boarding department was opened in 1956. Called St. Mary's residence, single rooms made up the majority of this building but at the front ends, there were double rooms, six in total, two on each floor, which were occupied by the college priests and latterly by brothers or prefects supervising the floors. Original stables were the open dormitories of Ardclinis, Trostan and Knochore. On the level above the Ardclinis Dormitory were the rooms of three priests. These old stables now house Music, Languages and Business Studies classrooms. The building is known as St Joseph's.
Sports facilities
The Tennis Courts were situated in a small field which in the 1950s and early 1960s was called the "Wee Field". The £1.6 million block for IT, Home Economics, Art and Science on the site of the old Tennis Courts. At the south end of the College grounds there is a wooded area in which the original owner's dog, Urisk, is buried. The headstone remains and on it is written:
"Here Urisk lies and let the truth be told, This faithful dog was blind, infirm and old. Deaf to all else his mistress' voice he knew, Blind though he was, his step to her was true. So strong an instinct by affection fed, Endured till Urisk's vital spirit fled. Stoop grandeur from thy throne ye sons of pride, To whom no want is known, nor wish denied. A moment pause, and blush, if blush you can, To find in dogs more virtue than in man. And share, 'midst all your luxury and pelf', one thought for others out of ten for self'".
At the north end, there are four sports pitches and a set of Hand-Ball alleys all of which are the 60 x 40 type of alley. Behind the squash courts, there is a new outdoor basketball court.
The seaward wall of the school has seven cannons facing the sea which are of naval origin from the Napoleonic wars. Towards the northern end of the sea-wall, there was a gate, lending access to a twisting path down to the Coast Road but the end of this path, where it met the Coast Road, was out-of-bounds. Just across the road and about 50 yards to the north, the Garron Point Post Office was located and the journey between the gate at the Coast Road and the Post Office was fraught with danger.
