Darcy, Hyacinth Talbot (1806–74), evangelical clergyman and landlord, was born at Glen Ierne, Clifden, son of John Darcy (see below) of a Connemara gentry family, one of the fourteen ‘Tribes of Galway’. A private tutor, Mr Hawkesworth, prepared Hyacinth for the undergraduate course at TCD, where he entered as a fellow commoner on 5 November 1821 at fifteen years of age. However, he failed to complete his studies and came home to manage his father's estate. While convalescing after an operation to amputate one of his legs, Hyacinth had a conversion experience; thereafter he was a staunch protestant and strongly supported the evangelical protestantism of the day. Archbishop Power le Poer Trench (qv), who was promoting an aggressive proselytising campaign in his Tuam archdiocese, befriended Hyacinth, who was elected treasurer of the Connemara Christian Committee at a meeting in Clifden on 11 February 1836. This group planned the evangelisation of the locality and upon the death of his father in 1839, Hyacinth Darcy, who had organised weekly prayer meetings at the church in Clifden since 1838, became an active missionary, distributing Bibles to his tenants and aiding evangelical clergymen in their efforts to convert catholics. The work of Darcy and the Connemara Christian Committee formed the foundation for the establishment of the Society of Irish Church Missions (SICM), an evangelical agency founded in 1845 by the rector of Wonton, Hampshire, Alexander Dallas (qv), who hoped to use Connemara as a base of operations for his proselytising mission in the west of Ireland. Darcy agreed to help Dallas to establish missionary stations among the local people, and in places such as Omey, Ballyconree, and Moyrus, all in Co. Galway, the SICM made significant conversions. The Clifden area, which in 1838 had a single protestant church with twenty-five worshippers, in 1863 had ten churches for more than 250 communicants.
Darcy did his utmost to relieve the populace during the famine of the 1840s, but the difficulties bankrupted him, and in 1849 he had to sell his estate (mortgaged since his father's time) in the encumbered estates court; in 1851 his former tenants became his parishioners when Archbishop Thomas Plunket (qv) ordained him and made him rector of Clifden, giving Dallas another weapon in his proselytising arsenal. Unlike many of his fellow evangelicals, Darcy was highly popular with the peasantry, whom he helped during difficult times. Visitors to the area, such as Robert Jocelyn (qv), 3rd earl of Roden, who reported on the progress of protestantism in the west of Ireland in 1851, commented on Darcy's compassion and affable demeanour. Later Archbishop Plunket rewarded him by making him rector and vicar of Omey, Ballindoon, and Moyrus. Darcy remained diligent in evangelical work for the remainder of his life. He contemplated running for parliament as a liberal candidate in 1872, but decided against entering politics. He died at Clifden 2 September 1874.
Hyacinth Darcy married, first, on 8 June 1852, Fanny Bellingham, who was possibly of the Castle Bellingham family; she had been a committed supporter of Alexander Dallas. She died, childless, on 26 June 1854. He married, secondly, on 24 January 1862, Mary Anne, daughter of John Newman of Brands House, Buckinghamshire, with whom he had three daughters.
His father, John Darcy (1785–1839), improving landlord and founder of the town of Clifden, Co. Galway was born 26 November 1785, to Hyacinth Darcy and his first wife, Mary Blake; his father was a first cousin of Count Patrick Darcy (qv) (d. 1779). John Darcy became a protestant on 2 May 1800, probably in order to circumvent possible inheritance problems, but all his life remained sympathetic to his former co-religionists. In 1804 he inherited extensive estates in east Galway and Mayo from a Darcy second cousin, and he was high sheriff of Co. Galway in 1811. It was around this time that, determined to improve both his estate and the living conditions of his tenantry, he moved from the family's original home at Killulta, Co. Galway, to Clifden, on the coast in the centre of his western estates, and renovated Clifden Castle in the neo-Gothic style then fashionable. He vigorously lobbied the government for financial assistance for the area, which was very poor and beset by frequent famines. He realised that better communications were essential, and after a famine in the 1820s persuaded the government to build a pier at Clifden to improve commerce by sea. Alexander Nimmo (qv) completed the work in 1831. By that date Darcy had managed to establish direct trade with Liverpool, sending shipments of herrings caught by local boats, and had also encouraged the establishment of marble quarries and woollen mills. In 1822 there was only one slated house in the village; by 1831 there were thirty shops and two hotels, serving a population of over 2,000. Roads had been improved and markets were held in the new town. He opposed the proselytising efforts of archbishop Power le Poer Trench and his colleagues, and even sacked his children's tutor, Alexander Campbell, for insulting the local people and their priests.
John Darcy married, first, on 4 June 1804, Frances Blake, daughter of Andrew Blake of Castle Grove and niece of Viscount Netterville; she died 15 April 1815, having borne four sons and two daughters. He married, secondly, on 3 March 1821, Louisa Bagot Sneyd (d. 1874), daughter of Henry Sneyd, with whom he had four sons and two daughters. Darcy died 10 October 1839. He was succeeded in his estates by the eldest son of his first marriage.