Taghmon (Tachmon), Hugh de (d. 1282), bishop of Meath, treasurer, and justiciar of Ireland, was of an Anglo-Irish family from Taghmon in Co. Westmeath. As he was frequently styled ‘magister’, he may have held an MA from Oxford. He first appears in the records as a canon of Meath at the time of his election to the bishopric in 1252 (before 23 December). His nomination occasioned a bitter dispute with the archbishop of Armagh, then in Rome, who, believing the election had taken place outside the prescribed canonical period, assumed the right devolved to him as metropolitan to appoint a bishop. A two-year struggle ensued between Taghmon and the archbishop's nominee, during which Taghmon ruthlessly excommunicated any within his diocese who backed his rival; he was also vociferously supported by Henry III and the Lord Edward, who had given Taghmon's election their blessing. He was finally confirmed as bishop of Meath by Innocent IV on 31 October 1254. The following year he successfully petitioned Rome for permission to build a cathedral in his diocese. In 1260–62 he attempted to have Meath exempted from visitation by the archbishop of Armagh, but at the provincial synod of Drogheda in 1262 the metropolitan's rights were upheld.
Taghmon was treasurer of Ireland from c.1260 to Trinity 1274 and briefly acted as a justice itinerant in 1260. He was appointed justiciar of Ireland on 10 June 1265 by the desperate Montfortian regime in England – one of three ineffective appointments to the justiciarship during Montfort's hegemony – though there is no evidence to suggest that he was overtly sympathetic to the baronial cause. Following an audit of his accounts in 1280 it was found that much of the pertinent information was missing, either ‘through accident or carelessness’, and he was personally charged with discrepancies by the auditors. After Hugh protested to the king the debt was waived. Described by the Anglo-Irish annals as a pious and venerable man, he died in 1282, before 6 January, and was buried at Mullingar.