Winifred Maxwell, Countess of Nithsdale (c.1680–1749), formerly Lady Winifred Herbert, is best known for arranging the daring escape of her husband from the Tower of London in 1716.
Her father was the 1st Marquess of Powis, and she married, on 2 March 1699, the 5th Earl of Nithsdale, a Catholic nobleman. The couple had met at the French court, where Lady Winifred's father was in exile, while Nithsdale was paying his respects to the former King James II of England (James VII of Scotland). While resident at Terregles, Dumfriesshire, Scotland, the couple had five children.
In 1715, Nithsdale joined the Jacobite rebellion, but he was captured at the Battle of Preston and sent to the Tower of London. Having been tried for treason, he was sentenced to death, despite Lady Nithsdale's personal appeal to King George I. On the night before his execution, she persuaded the guards to let her see him, dressed him in women's clothing (including the "Nithsdale Cloak", which is still held by the family) and smuggled him out. They escaped to France, and went from there to Rome in the retinue of the Old Pretender.