Castleknock (Irish: Caisleán Cnucha) is an affluent suburb located 8 km (5 mi) west[3] of the centre of Dublin city, Ireland.

[4][5] In addition to the suburb, the name "Castleknock" also refers to older units of land division: a townland,[4 1] a civil parish[4 2] and a barony.

Cnucha, the daughter of Concadh Cas, From the land of Luimncach broad and green, Died yonder in that house To the horror of the Gaels.

that the name Castleknock is rooted in the topography of the hill or cnoc located at the centre of the modern neighbourhood and/or the personal name of the mother of a semi-legendary High King i.e. Cnucha and the building of a castle by Normans on this site in the 12th century.

In September 919, Niall gathered the Irish Chiefs and their armies at Castleknock from where they led a fight against the Danes who had regained their power over Dublin.

The siege exerted pressure on the forces of the Cambro-Norman leader, Strongbow, who asked the Archbishop of Dublin, Lawrence O'Toole to negotiate with the High King at Cnucha.

Strongbow was furious but Maurice de Prendergast, who had accompanied Archbishop O'Toole, had observed that the Irish troops were largely inactive and unready for battle.

In 1185, the second baron, Richard de Tyrell, gave a grant of land to the Benedictine Monks of the Abbey of Little Malvern, Worcestershire, to endow a religious house at Castleknock in honour of Saint Brigid.

In 1219 the great tithes of the parish were appropriated by Archbishop Henry de Londres to the Priory of Malvern on condition that they should add five monks to their number.

[13] The spire was added in 1864 by friends of the late James Hans Hamilton as a memorial to the 1st Baron Holmpatrick of Abbottown and MPfor the County of Dublin.

These included the Guinnesses at Farmleigh, and Knockmaroon, the Laidlaws at Abbey Lodge, the Godleys at Oatlands, and the Brookes at Sommerton House.

Although they left Farmleigh in 1999, the Guinness family are still present in Castleknock at Knockmaroon House and its Demesne, located on Carpenterstown Road and the seat of Lord Moyne.

[16] The neighbourhood is bordered to the west by the large suburb of Blanchardstown, to the east by the Phoenix Park, to the north by Dunsink and to the south by the village of Chapelizod above the Liffey valley.

The area can be accessed from Junction 6 on the M50 motorway, on either side of which it lies, from the R147 Navan Road, from Chesterfield Avenue and the Castleknock Gate of the Phoenix Park, and via Knockmaroon Hill in Chapelizod.

The branches come together near the area known as the Sand Holes or Sandpits in Diswellstown, and the stream flows directly south to join the Liffey.

A fee-paying secondary school for girls, Mount Sackville, under the care of the Sisters of St. Joseph of Cluny, is located on Tower Road, Knockmaroon Hill, Chapelizod.

The suburb is also home to Castleknock College, a voluntary Vincentian secondary school for boys which has produced numerous alumni in the fields of arts, politics, sports, science and business.

Brookes of Somerton House, Castleknock, to commemorate members of his family, whereas the Harry Clarke window in St Thomas the Apostle was donated by the Dominican Order after their convent at Dún Laoghaire closed in 1991.