William Mackenzie, 5th Earl of Seaforth

William Mackenzie, 5th Earl of Seaforth
Earl of Seaforth
Seaforth as a boy
Tenure	1701–1716 (Attainted)
Predecessor	Kenneth Mackenzie, 4th Earl of Seaforth
Successor	Kenneth Mackenzie, Lord Fortrose
Born	Unknown
Died	8 January 1740 Isle of Lewis
Nationality	Scottish
Spouse(s)	Mary Kennet ​ (m. 1715)​
Issue	Kenneth Mackenzie, Lord Fortrose The Hon. Ronald Mackenzie The Hon. Nicholas Mackenzie Lady Frances Mackenzie
Parents	Kenneth Mackenzie, 4th Earl of Seaforth Lady Frances Herbert

William Mackenzie, 5th Earl of Seaforth (died 1740), and 2nd titular Marquess of Seaforth (in the Jacobite Peerage), also known as Uilleam Dubh, or Black William, was a Scottish peer and head of Clan Mackenzie. Educated in France and brought up as a Roman Catholic, he was attainted for his part in the 1715 Jacobite Rising and also joined the 1719 Rising.

He was pardoned in 1726 and allowed to return home, although the title Earl of Seaforth remained forfeit. He died on 8 January 1740 on the Isle of Lewis and was buried in the ancient church of Ui.^[1]