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,
Chatham Islands landed on 29 November 1791, claimed possession for Great Britain and named the islands after the First Lord of the Admiralty, John Pitt, 2nd Earl of Chatham. A relative of his, Thomas Pitt, was a member of the Vancouver Expedition. Sealers and whalers soon started hunting in the surrounding ocean with the islands as their base. It is estimated that 10 to 20 percent of the indigenous Moriori soon died from diseases introduced by foreigners. The sealing and whaling industries ceased activities about 1861, while fishing remained as a major economic activity. Chatham Islands date their anniversary on 29 November,