William Southwell

William Southwell (1669 – 23 January 1720) was an Irish politician and British Army officer.

Background He was the third son of Richard Southwell of Castle Matrix, County Limerick, and his wife Lady Elizabeth O'Brien, daughter of Murrough O'Brien, 1st Earl of Inchiquin. His older brothers were Thomas Southwell, 1st Baron Southwell and Richard Southwell.

Career Southwell entered the British Army under King William III of England in 1693. During the Nine Years' War, he was wounded at the 2nd Siege of Namur in 1695 and was afterwards promoted to captain. He was promoted to lieutenant-colonel a year later.

Family In 1709, he married Lucy Bowen, younger daughter of William Bowen, of Ballyadams, County Laois, a grandson of Sir William Domville, Attorney General for Ireland. By her he had six sons and nine daughters.