Countess Ekaterina Semyonovna Vorontsov (October 24, 1784 in Saint Petersburg – March 27, 1856 in London), sometimes spelled Woronzow, was the daughter of Semyon Vorontsov, the Russian ambassador in Britain from 1785, and the only sister of Prince Mikhail Vorontsov, Viceroy of New Russia and Caucasus (1782–1856). She was also a niece of Princess Dashkova, a friend of Catherine the Great and a conspirator in the coup d'état that deposed Czar Peter III and put his wife on the throne.
In 1808, she married George Herbert, 11th Earl of Pembroke as his second wife and became Countess of Pembroke, Lady Pembroke, the chatelaine of Wilton House, Wiltshire. The Wilton Estate, Salisbury held an exhibition on her life titled Through Russian Eyes in August 2008. Her letters show her to have been a shrewd observer of European politics.
|Lady Elizabeth Herbert||1809||1858||married Richard Meade, 3rd Earl of Clanwilliam had issue|
|Hon. Sidney||16 September 1810||2 August 1861||Caroline Norton (affair) had no issue; married Mary Elizabeth Ashe à Court-Repington and had issue. He was made Baron Herbert of Lea in 1861. The current Earl of Pembroke descends from his second son who inherited the title in 1895.|
|Lady Mary Herbert||1813||1892||married George Brudenell-Bruce, 2nd Marquess of Ailesbury had no issue|
|Lady Catherine||31 October 1814||12 February 1886||married Alexander Murray, 6th Earl of Dunmore had issue|
|Lady Georgiana Herbert||1817||1841||married Henry Petty-Fitzmaurice, 4th Marquess of Lansdowne had no issue; she is Henry's 1st wife|
|Lady Emma||1819||1884||married Thomas Vesey, 3rd Viscount de Vesci had issue|