Rear-Admiral The Hon. William Le Poer Trench (4 July 1771 – 14 August 1846) was born in Garbally, Galway, Ireland to William Power Keating Trench, 1st Earl of Clancarty and Anne Gardiner. He was married twice, first on 8 March 1800 to Sarah Cuppage, daughter of John Loftus Cuppage. Sarah died in June 1834, and on 1 February 1837 William married a second time to Margaret Downing, daughter of Dawson Downing and Anne Boyd. He acted for a considerable period as the agent of the estates of his father's family in Ireland.