Earl of Londonderry extinct on the death of his great-grandson, the fourth Earl, in 1714. The second creation came in 1726 in favour of the soldier and politician Thomas Pitt, 1st Baron Londonderry. He had already been created Baron Londonderry in 1719 and was made Viscount Gallen-Ridgeway at the same time as he was granted the earldom, also in the Peerage of Ireland. He was the husband of Lady Frances Ridgeway, daughter and heiress of the fourth Earl of the first creation. A member of the prominent Pitt family, he was the uncle of William Pitt, 1st Earl of Chatham. His younger son,
Earl of Chatham her husband had wished to remain a member of the House of Commons. Their second son was William Pitt the Younger, who became the country's youngest Prime Minister in 1783, at the age of 24. Their eldest son, John Pitt, inherited the earldom and viscountcy in 1778 and the barony in 1803. Upon his death in 1835, all three titles became extinct. The second creation of this title came in 1761 in favour of Lady Hester Pitt; the first creation was for John Campbell, 2nd Duke of Argyll and hence the Duke of Argyll. Earl of Chatham Earl of Chatham,