Le Fanu, William Richard (1816–94), civil engineer and commissioner of public works, was born 24 February 1816 in the Royal Hibernian Military School, Phoenix Park, Dublin, youngest child among two sons and a daughter of the Very Rev. Thomas Philip Le Fanu (1784–1845), dean of Emly and rector of Abington, and Emma Lucretia Le Fanu (née Dobbin) of Finglas. William spent his early years in Dublin, but the family moved to Limerick in 1826 when Thomas Philip was appointed dean. His brother was the novelist Joseph Thomas Sheridan Le Fanu (qv), and the two were home schooled by a tutor, were taught English and French by their father, and entered TCD together in the 1830s. After graduating with a BA (1839), Le Fanu became a pupil of the eminent engineer John Macneill (qv). At first he worked on extensive sea-reclamations, harbours, and other nautical works, but with the coming of the railway he was drawn to railroad engineering.
Le Fanu quickly established himself as one of Macneill's principal assistants, and was initially involved in the construction of the lines from Dublin to Drogheda, Cashel, and Carlow (1840–46). In 1846 he was appointed resident engineer in charge of the completion of the Great Southern & Western Railway line to Cork, and he was later established as the GS&WR's consulting engineer. Under his new title, he supervised the extension of the railway to Killarney, Tralee, Tullamore, Athlone, Roscrea, Nenagh, Malloy, and Fermoy. The years 1853–63 were particularly fruitful: Le Fanu became the main engineer for the Dublin, Wicklow & Wexford and Waterford–Limerick railways; he designed the Cahir viaduct and drafted plans for the Limerick–Foynes and Bagnalstown–Ballywilliam lines; and he served as consulting engineer to the Cork & Bandon railway company. He was also the consulting engineer (1861–3) to the board in charge of Irish lighthouses, but performed no work of any note in that capacity.
In 1863 he was offered the post of commissioner of public works, but hesitated in accepting because he enjoyed the freedom and remuneration of private practice. His friends in the Irish government eventually convinced him to accept the job, and from then on he wholly devoted himself to the office (1863–90). In his capacity as commissioner he was responsible for public works and sanitary loans, landed property improvements, land drainage, and all matters connected with inland navigation, harbours, piers, and fisheries. He was an able and efficient commissioner who never allowed his work to accumulate and, except during his annual holidays or while out on inspection, he was hardly ever absent from the office of public works. Le Fanu retired in 1890, and on 8 September 1894 he died at his residence, Summerhill, Enniskerry, Co. Wicklow. He was buried in his local churchyard. A friendly and outgoing man, he was a popular figure in Dublin's social and literary circles, and had many prominent friends. Despite his many years working on Irish railways and as a public works commissioner, he was surprisingly better remembered as a ‘successful contributor to the contemporary literature of gossip and anecdote’ (FJ, 11 Sept. 1894) and as ‘a noted raconteur’ (IBL, vi (Dec. 1914), 79) than as an engineer.
Le Fanu married (15 January 1857) Henrietta Victorine, sixth daughter of Sir Matthew Barrington (qv), 2nd baronet and crown solicitor for Munster, and Charlotte Hartigan, daughter of a Dublin doctor. They had eight children, including Thomas Philip Le Fanu (1858–1945), CB and president of the Royal Society of Antiquaries of Ireland, and the Rev. Henry Frewen Le Fanu (qv), primate of Australia. Le Fanu was particularly close to his brother and his sister, Catherine Francis Le Fanu (1813–41), and was greatly saddened by her untimely death. Sheridan Le Fanu wrote two poems expressly for William to recite (‘Phaudhrig Crohoore’ and ‘Shamus O'Brien’), and dedicated All in the dark (1866) to his brother ‘with great affection and admiration.’ Le Fanu was a longstanding member of the RIA (elected 10 February 1845). His light and anecdotal autobiography, Seventy years of Irish life, was published in 1893 and reissued in 1914.