Clongowes Wood College SJ is a Catholic voluntary boarding school for boys near Clane, County Kildare, Ireland, founded by the Jesuits in 1814. It features prominently in James Joyce's semi-autobiographical novel A Portrait of the Artist as a Young Man. One of five Jesuit secondary schools in Ireland, it had 450 students in 2019.

The school's current headmaster, Christopher Lumb, is the first lay headmaster in its history.

The school is also a member of the Headmasters' and Headmistresses' Conference being one of only three members based in the Republic of Ireland.

The school is a secondary boarding school for boys from Ireland and other parts of the world. The school is divided into three groups, known as "lines". The Third Line is for first and second year students, the Lower Line for third and fourth years, and the Higher Line for fifth and sixth years. Each year is known by a name, drawn from the Jesuit Ratio Studiorum: Elements (first year), Rudiments (second), Grammar (third), Syntax (fourth), Poetry (fifth), and Rhetoric (sixth).

The medieval castle was originally built in the 13th century by John de Hereford, an early Anglo-Norman warrior and landowner in North Kildare. He had been given extensive lands in the area of Kill, Celbridge and Mainham by his brother, Adam de Hereford, who had come to Ireland with 'Strongbow', the Earl of Pembroke.

The castle is the residence of the religious community and was improved by a "chocolate box" type restoration in the 18th century. It was rebuilt in 1718 by Stephen Fitzwilliam Browne and extended in 1788 by Thomas Wogan Browne. It is situated beside a ditch and wall—known as ramparts—constructed for the defence of the Pale in the 14th century. The building was completely refurbished in 2004 and the reception area was moved back there from the "1999 building."

The castle is connected to the modern buildings by an elevated corridor hung with portraits, the Serpentine Gallery referred to by James Joyce. This gallery was completely demolished and rebuilt in 2004 as part of a redevelopment programme for the school buildings.

In 1929 another wing was built at a cost of £135,000, presenting the rear façade of the school. It houses the main classrooms and the Elements, Rudiments, Grammar and Syntax dormitories.

An expansion and modernisation was completed in 2000; the €4.8m project added another residential wing that included a 500-seat dining hall, kitchen, entrance hall, offices, and study/bedrooms for sixth year ("Rhetoric") students.

The Boys' Chapel has an elaborate reredos, a large pipe organ in the gallery, and a sequence of Stations of the Cross painted by Sean Keating. School tradition has it that the portrait of Pontius Pilate in the 12th station was based on the school rector, who had refused to pay the artist his asking price.

The moat that outlines the nearby forest of the college is the old border of The Pale, with the Wogan-Browne castle (now the residence of the Jesuit community) landmarking its edge.

The school traces its history back to a 799-acre (3.23 km) estate owned by the Wogan family in 1418 under the reign of Henry IV. The name "Clongowes" comes from the Irish for "meadow" (cluain) and for "blacksmith" (gobha). The estate was originally known as "Clongowes de Silva" (de Silva meaning "of the wood" in Latin). The estate later passed to the Eustace family and became part of the fortified border of the Pale in 1494. The Eustaces lost their estates during the Restoration (1660). The estate was sold by the Wogan-Brownes to the Jesuits in March 1814 for £16,000.

The school accepted its first pupil, James McLornan, on 18 May 1814.

In 1886 the Jesuit-run St Stanislaus College in Tullabeg, County Offaly, was amalgamated with Clongowes Wood College.

Joseph Dargan served as rector in the 1970s. Leonard Moloney was the headmaster from 2004 to 2015. Michael Sheil retired as rector in 2006 and Bruce Bradley (headmaster 1992–2000) was his successor. In September 2011 Michael Sheil returned as rector.

As of 2021, there are four Jesuits living at the school. Two priests and two brothers.

Clongowes is also part of an initiative to ease religious tensions in Turkey, currently being headed by Alan McGuckian (former teacher in Clongowes now Bishop of Raphoe) in Istanbul.

• Francis Mahony
• John Conmee (1883-1887)
• James Daly (1887-1916)
• Larry Kieran (1917-1925)
• Mathias Bodkin (1933-1937)
• Brian McMahon (1944-1947)
• Hilary Lawton (1948-1959)
• Raymond J Lawler (1959-1962)
• Joseph Marmion (1962-1965)
• Paddy Crowe (1971–1976)
• Philip Fogarty (July 1976 – Aug 1987)
• Liam O'Connell (1987-1992)
• Bruce Bradley (1992-2000)
• Dermot Murray (2000–2004)
• Leonard Moloney (2004–2015)
• Chris Lumb (2015–present) – first lay headmaster

• Fr. Peter Kenney (1814–17) – founder of the college
• Fr. Charles Aylmer (1817–20) – took out lease of land for Tullabeg College
• Fr. Bartholomew Esmonde (1820-21)
• Fr. Peter Kenney (1821–30)
• Fr. Bartholomew Esmonde (1830–36)
• Fr. Robert Haly (1836–41)
• Fr. Robert St. Leger (1841-42)
• Fr. Robert Haly (1842-50)
• Fr. Michael Kavanagh (1850–1855)
• Fr. Joseph Lentaigne (1855-58)
• Fr. John McDonald (1858-60)
• Fr. Eugene Browne (1860-1870)
• Fr. Robert Carbery (1870-1876)
• Fr. Thomas Keating (1876-81)
• Fr. Edward Kelly (1881-85)
• Fr. John Conmee (1885-91)
• Fr. Matthew Devitt (1891-1900)
• Fr. Michael Browne (1900)
• Fr. James Brennan (1900-04)
• Fr. Vincent Byrne (1904-07)
• Fr. Matthew Devitt (1907-08)
• Fr. Thomas Nolan (1908-12)
• Fr. Nicholas Tomkin (1912-19)
• Fr. Charles Mulcahy (1919–1922)
• Fr. John Joy (1922-27)
• Fr. George Roche (1927-33)
• Fr. Hilary Lawton (1959-65)
• Fr. Frank Joy (1965-68)
• Fr. Paddy Crowe (1968–71)
• Fr. Jack Brennan (1972-77)
• Fr. Joseph Dargan (1977–1979)
• Fr. Paddy Carberry (1980–1983)
• Fr. Kieran Hanley (1983–89)
• Fr. Patrick Crowe (1992-95)
• Fr. Dermot Murray (1995–2000)
• Fr. Michael Sheil (2000–06)
• Fr. Bruce Bradley (2006–11)
• Fr. Michael Sheil (2011–present)

One early history of the school is The Clongowes Record 1814–1932 by Timothy Corcoran (Browne and Nolan, Dublin, 1932). A half-century later, a history was written by Roland Burke Savage and published in The Clongownian school magazine during the 1980s; that same decade, Peter Costello wrote Clongowes Wood: a History of Clongowes Wood College 1814–1989, published by Gill and Macmillan, Dublin, 1989).

Clongowes is known for its strong pedigree in rugby union. Despite a relatively small size, Clongowes has won the Leinster Schools Rugby Senior Cup nine times, winning its first final in 1926. Following this, there was a gap of 52 years until the next title in 1978. Beginning with a 3rd title in 1988 and up until 2011, Clongowes has appeared in 13 finals, more than any other school in the competition during this period. Clongowes secured a first set of back-to-back titles with wins in 2010 and 2011 before being awarded a joint title in the 2020 season which was cut short because of the COVID-19 pandemic.

The school featured prominently in James Joyce's semi-autobiographical novel A Portrait of the Artist as a Young Man. A documentary depicting a year in the life in the school was screened in 2001 as part of RTÉ's True Lives series. The popular fictional series of Ross O'Carroll Kelly has mentioned Clongowes Wood on a number of occasions in the book and Irish Times column.

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• List of Jesuit schools
• List of Jesuit sites in Ireland
• List of alumni of Jesuit educational institutions
• Our Lady's Children's Hospital, Crumlin

• Clongowes Wood College website
• Clongowes Youth Club