Mary Watson Wentworth, Marchioness of Rockingham

Mary Watson-Wentworth, Marchioness of Rockingham (; 1735 – 19 December 1804) was the wife of Charles Watson-Wentworth, 2nd Marquess of Rockingham, who was prime minister of Great Britain in 1782, and previously from 1765 to 1766.

Early life Born in Pontefract, West Yorkshire, England, she was the only child and heiress of Thomas Liddell, Lord of the Manor of Ecclesall, South Yorkshire, and Margaret Norton.

Marriage On 26 February 1752, Mary Bright married Whig politician Charles Watson-Wentworth. She was described by herself and others as Rockingham’s "secretary", but Rockingham called her "My Minerva at my elbow." After Rockingham’s death, her correspondent Edmund Burke wrote to her, "Your Names indeed ought to go down together; for it is no mean part you have had in the great services which that great and good man has done to his Country."

Lady Rockingham was the owner of Rockingham Mantua, a silk satin mantua brocaded in silver thread with silver lace trim. It is thought that the Mantua was part of a matching set with her husband. Lady Rockingham mentioned the sets in her letters "Lord Stormont says being in your dress is quite bourgeois, but I hope you will approve of it, I shall take it monstrous if you don't, for I mean it as a compliment to you".

The widowed Lady Rockingham settled at Hillingdon House, Middlesex, in 1785, where she died in 1804 and was buried with her husband at York Minster.