Viscount Gormanston is a title in the Peerage of Ireland held by the head of the Preston family. It was created in 1478. The holder is the senior Viscount of Ireland, as well as the bearer of the oldest vicomital title in either Britain or Ireland. The Preston family descends from Sir Robert Preston, who served as Lord Chancellor of Ireland. Sometime between 1365 and 1370 he was created Baron Gormanston in the Peerage of Ireland by writ. His son, the second Baron, played a prominent part in public affairs and was arrested for treason in 1418. His great-grandson, the fourth Baron, served as Lord Deputy of Ireland. In 1478 he was created Viscount Gormanston in the Peerage of Ireland. His great-great-great-great-grandson, the seventh Viscount, was a supporter of King James II and was outlawed after the Glorious Revolution.
Jenico Preston helped to suppress the Irish Rebellion of 1798. In 1800 he had the outlawry reversed and was summoned to the Irish House of Lords as the twelfth Viscount Gormanston. He was the great-grandson of Anthony Preston, the de jure ninth Viscount Gormanston, the nephew of the seventh Viscount. The twelfth Viscount was succeeded by his son, the thirteenth Viscount. In 1868 he was created Baron Gormanston, in the County of Meath, in the Peerage of the United Kingdom, which gave the Viscounts an automatic seat in the House of Lords. His son, the fourteenth Viscount, notably served as Governor of British Guiana and as Governor of Tasmania. As of 2014[update] the titles are held by the latter's great-grandson, the seventeenth Viscount who succeeded to the titles in 1940 at the age of seven months after his father was killed during the Battle of France in the Second World War.
Another member of the Preston family was Thomas Preston, 1st Viscount Tara. He was the second son of the fourth Viscount Gormanston. Also, John Preston, 1st Baron Tara, was a descendant of a younger brother of the first Viscount Tara.
The unusual first name Jenico derives from the Gascony-born soldier Sir Jenico d'Artois, a prominent military commander who became a substantial landowner in Ireland. His daughter Jane married the 3rd Baron Gormanston, and was mother to the 1st Viscount.
Barons Gormanston (1365–1370)
- Robert Preston, 1st Baron Gormanston (died 1396)
- Christopher Preston, 2nd Baron Gormanston (died 1422)
- Christopher Preston, 3rd Baron Gormanston (died 1450)
- Robert Preston, 4th Baron Gormanston (died 1503) (created Viscount Gormanston in 1478)
Viscounts Gormanston (1478)
- Robert Preston, 1st Viscount Gormanston (1435–1503)
- William Preston, 2nd Viscount Gormanston (died 1532); only son of the 1st Viscount
- Jenico Preston, 3rd Viscount Gormanston (1502–1569); only son of the 2nd Viscount
- Christopher Preston, 4th Viscount Gormanston (1546–1599); eldest son of the 3rd Viscount
- Jenico Preston, 5th Viscount Gormanston (1584–1630); eldest son of the 4th Viscount
- Nicholas Preston, 6th Viscount Gormanston (1608–1643); only son of the 5th Viscount
- Jenico Preston, 7th Viscount Gormanston (died 1691) (outlawed 1691); eldest son of the 6th Viscount
- Jenico Preston, de jure 8th Viscount Gormanston (1640–1700); eldest son of 2nd and youngest son of the 6th Viscount
- Anthony Preston, de jure 9th Viscount Gormanston (died 1716); only brother of the de jure 8th Viscount
- Jenico Preston, de jure 10th Viscount Gormanston (1707–1757); only son of de jure 9th Viscount
- Anthony Preston, de jure 11th Viscount Gormanston (1736–1786); eldest son of the de jure 10th Viscount
- Jenico Preston, 12th Viscount Gormanston (1775–1860) (restored 1800); only son of the de jure 11th Viscount
- Edward Anthony John Preston, 13th Viscount Gormanston (1796–1876); eldest son of the 12th Viscount
- Jenico William Joseph Preston, 14th Viscount Gormanston (1837–1907); eldest son of the 13th Viscount
- Jenico Edward Joseph Preston, 15th Viscount Gormanston (1879–1925); eldest son of the 14th Viscount
- Jenico William Richard Preston, 16th Viscount Gormanston (1914–1940); eldest son of the 15th Viscount; killed in action, France, World War II
- Jenico Nicholas Dudley Preston, 17th Viscount Gormanston (born 1939); only son of the 16th Viscount
The heir apparent is the present holder's eldest son Hon. Jenico Francis Tara Preston (born 1974)
- The Observer; Dublin Castle, July 16, 1798, 22 July 1798
- Kidd, Charles, Williamson, David (editors). Debrett's Peerage and Baronetage (1990 edition). New York: St Martin's Press, 1990.
- Tiernan, Sonja, ‘“A Zealous Catholic and a Notorious Trouble-Maker:” The Gormanston Papers in the National Library of Ireland’ in Ríocht na Mídhe: Meath Archaeological and Historical Society. Vol. XX, 2009, pp. 171–88.
- Catelogue for Gormanston Estate Papers at National Library of Ireland. http://www.nli.ie/pdfs/mss%20lists/132_GormanstonPapers.pdf
- Leigh Rayment's Peerage Pages [self-published source][better source needed]