William BLAYNEY 6th Lord Baron Monaghan 
- Born: 1670, Ireland
- Marriage (1): Hon Mary CAULFEILD  in 1686
- Died: 3 Jan 1705/06, Castle Blayney Dublin IRL aged 36
- Buried: 5 Jan 1705/06, Chapel of Castle Blayney co Mongahan IRL
William Blayney, 6th Lord Blayney, Baron of Monaghan was the son of Richard Blayney, 4th Lord Blayney, Baron of Monaghan and Elizabeth Vincent. He married Hon. Mary Caulfeild, daughter of William Caulfeild, 1st Viscount Charlemont. and Hon. Sarah Moore, in 1686. He died on 3 January 1705/6 at Dublin, County Dublin, Ireland. He was buried on 5 January 1705/6 at Chapel of Castle Blayney, County Monaghan, Ireland.
In 1689 he was attainted as a resident of England, but was later restored. He succeeded to the title of 6th Lord Blayney, Baron of Monaghan, co. Monaghan [I., 1621] in August 1689. He held the office of Governor of County Monaghan.
William married Hon Mary CAULFEILD  [MRIN: 4512], daughter of William CAULFEILD 1st Viscount Charlemont  and Hon Sarah MOORE , in 1686. (Hon Mary CAULFEILD  was born in 1659 in Charlemont Armagh IRL, died on 8 Aug 1724 and was buried in Christ Church Cathedral Dublin.)