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,
Hester Pitt, Countess of Chatham Hester Pitt, Countess of Chatham Hester Pitt, Countess of Chatham, 1st Baroness Chatham (; 8 November 1720 – 9 April 1803), who was Baroness Chatham in her own right, was the wife of William Pitt (the Elder), 1st Earl of Chatham, who was Prime Minister of Great Britain from 1766 to 1768. The sister of George Grenville, who was Prime Minister from 1763 to 1765, she was also the mother of Prime Minister William Pitt the Younger and a niece of the noted Whig politician Richard Temple, 1st Viscount Cobham, who had served as her husband's mentor. Chatham and Elizabeth