The site for the Church and adjoining Convent was donated by the Calbeck Family of Moyle Park, Clondalkin. The foundation stone was laid in 1857 and the completed Church was dedicated in 1862. The Church is dedicated to St. Killian, a local saint and also to the Immaculate Conception. Designed by William Calbeck, a noted architect of the day, and is built in the Gothic revival style which had recently been introduced to Ireland by the famous English architect, A.W.N Pugin. This was his largest religious commission and is built of calp limestone quarried at Monastery Road, Clondalkin. The stained-glass windows are by Thomas Earley, who committed suicide while installing them. A further window marks the spot.