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 Rochford affairs. In 1688 he sailed with the prince on his famous expedition. After the Revolution he was naturalized and served the king in the field, being raised to the English peerage in 1695. He was succeeded by his son William, the second Earl, who was killed at the Battle of Almenar, and then by another son, Frederick, the third Earl. Frederick's son, William Henry, the 4th Earl, was a diplomat and a statesman. Having gained experience as envoy at Turin from 1749 to 1753, he was Ambassador to Madrid from 1763 to 1766 and to Paris from 1766 to 1768.