William Douglas, 4th Duke of Queensberry

The Duke of Queensberry
The Duke of Queensberry by John Opie
Born16 December 1724 (1724-12-16)
Peebles, Scotland
Died23 December 1810(1810-12-23) (aged 86)
London, England
Occupations
  • Landowner
  • racehorse owner
  • House of Lords representative peer
ChildrenMaria Seymour-Conway, Marchioness of Hertford (illegitimate)
Parent(s)William Douglas, 2nd Earl of March
Lady Anne Hamilton

William Douglas, 4th Duke of Queensberry, KT (16 December 1724 – 23 December 1810) was a Scottish nobleman and landowner. He was popularly known as Old Q (because that letter was painted on his carriage's door) and was reputed as a high-stakes gambler. In 1799 he was estimated the eighth-wealthiest man (or small family unit) in Britain, owning £1M (equivalent to £124,100,000 in 2023). He is one of ten known British millionaires that year, the royal family excluded.