Mary Elizabeth Townshend

Mary Elizabeth Pitt, Countess of Chatham (2 September 1762 – 21 May 1821), formerly Mary Elizabeth Townshend, was an English noblewoman and political campaigner. Her husband was John Pitt, 2nd Earl of Chatham.

Mary was the daughter of Thomas Townshend, 1st Viscount Sydney, and his wife, the former Elizabeth Powys. Her younger sister Frances (1772–1854) married George Rice, 3rd Baron Dynevor. Another sister, Harriet (1773–1814), married Charles Montagu-Scott, 4th Duke of Buccleuch.

She married the earl on 9 July 1783, at St George's, Hanover Square. Her brother-in-law, William Pitt the Younger, became prime minister later the same year, and Mary's father, a political ally, became Home Secretary in 1784. In 1799 her husband, the earl, became First Lord of the Admiralty. She was buried in the Pitt family vault in Westminster Abbey. Her marriage was childless and the earldom became extinct on her husband's death in 1835.