William Henn (c.1720 – 1796) was an Irish judge, who is remembered now mainly for the portrait of him in Jonah Barrington's Personal Sketches.
He was born at Ballynacally, County Clare, second son of Thomas Henn of Paradise Hill. The Henn family, who were originally from London, had acquired large estates in Clare in the 17th century. They had a long association with the law: Henry Hene, or Henn, who is generally thought to have been William's direct ancestor, was Chief Baron of the Irish Exchequer 1680-87. John Bennett, William's colleague on the Court of King's Bench, was a cousin.
William entered Middle Temple in 1738, took his degree as Bachelor of Arts from the University of Dublin in 1740, was called to the Irish Bar in 1744 and became King's Counsel in 1762. He was made a justice of the Court of King's Bench (Ireland) in 1768 and remained on the Bench until 1791. He died in Dublin in 1796.
Jonah Barrington called him a "very excellent private character" but did not rate his judicial qualities very highly. According to Barrington, Henn was "dreadfully puzzled" when he was hearing a case while on assize at Wexford in about 1789 by the arguments of two young barristers, each of whom pleaded with great eloquence that the law was in his client's favour. Having argued their contradictory positions at length, they requested the judge to give his ruling. Henn, at a loss as to which side was in the right, whispered to his registrar: "I wish to God I knew what the law really was!", to which the registrar replied that if he knew what the law was, he would happily share his knowledge with the judge.
John Scott, 1st Earl of Clonmell, who presided in the King's Bench where Henn was a junior judge, had a very low opinion of him, calling him "at best a fool". Admittedly Scott in his diary privately expressed his contempt for nearly all the Irish judges of his time, including some with whom he was outwardly friendly: Henn's cousin John Bennett he saw as his particular enemy.
William Henn married Elizabeth Parry; he was the father of William Henn junior, a Master in Chancery, and grandfather of Jonathan Henn, a barrister, who is best remembered for prosecuting John Mitchel. Sir Charles Villiers Stanford, the famous conductor and composer was his descendant in the next generation, the son of Jonathan's sister Mary who married John James Stanford.
- Ball, F. Elrington The Judges in Ireland 1221-1921 John Murray London 1926 Vol.2 p.216
- Henn, Francis Robert Notes on the Henn Family of Paradise County Clare
- Ball p.216
- Lenox-Conyngham, Melosina Diaries of Ireland Lilliput Press Dublin 1998 p.59
- Ball p.216
- Barrington, Jonah Personal Sketches of his Own Times Henry Colburn London 1827 Vol.1 pp.453-4
- Lenox-Conyngham p.59
- Ball p.175