Marcus Beresford, 1st Earl of Tyrone (16 July 1694 – 4 April 1763),[1] known as Sir Marcus Beresford, 4th Baronet, until 1720 and subsequently as The Viscount Tyrone until 1746, was an Anglo-Irish peer and politician.

He was the only son of Sir Tristram Beresford, 3rd Baronet, and his wife Nichola Sophia Hamilton, youngest daughter of Hugh Hamilton, 1st Viscount of Glenawly and his second wife Susanna Balfour.

[2] In 1715, he entered the Irish House of Commons, sitting for Coleraine until 1720,[3] when he was raised to the Peerage of Ireland with the titles Baron Beresford, of Beresford, in the County of Cavan, and Viscount Tyrone by King George I of Great Britain.

Together, they were the parents of seven sons and eight daughters, including:[7] Lord Beresford died at Tyrone House in Dublin and was succeeded in his titles by his fourth and oldest surviving son George.

[7] In 1767, four years after the earl's death, his widow claimed the title Baron La Poer and was shortly thereafter confirmed.