Katherine Wellesley-Pole, Countess Of Mornington

Katherine Wellesley-Pole, Countess of Mornington (23 January 1761 – 23 October 1851), was born Katherine Elizabeth Forbes. She was the daughter and co-heiress of Admiral Hon. John Forbes and Lady Mary Capell, daughter of William Capell, 3rd Earl of Essex. Her sister was Maria, who became the Countess of Clarendon.

On 17 May 1784, Katherine Forbes married William Wesley-Pole in London. William later adopted the surname Wellesley-Pole in 1789, aligning with the practice of other family members. He was known as Wellesley-Pole before receiving the peerage. Their marriage produced one son and three daughters: William Pole-Tylney-Long-Wellesley, who became the 4th Earl of Mornington; Lady Mary Charlotte Anne Wellesley; Lady Emily Harriet Wellesley; and Lady Priscilla Anne Wellesley.

Their children and their marriages include:

- William Pole-Tylney-Long-Wellesley (later 4th Earl of Mornington), who inherited his father's titles.

- Lady Mary Charlotte Anne Wellesley, who married Sir Charles Bagot, Bart., G.C.B., on 22 July 1806. Their union resulted in three sons and five daughters.

- Lady Emily Harriet (1792–1881), married Lord FitzRoy Somerset, later 1st Baron Raglan, in 1814.

- Lady Priscilla Anne (1793–1879), who married John Fane, Lord Burghersh, later 11th Earl of Westmorland.

In 1821, William Wellesley-Pole was elevated to the title of Baron Maryborough, and Lady Katherine became Lady Maryborough. When William inherited the earldom of Mornington from his older brother Richard Wellesley in 1842, Katherine assumed the title of Countess of Mornington.

William Wellesley-Pole died in 1845, at which point the earldom was inherited by their eldest son. Katherine died in her residence in Grosvenor Square, London, and was buried alongside her husband and other family members at Grosvenor Chapel.

A watercolour portrait of Katherine Wellesley-Pole, created by William Wood, was given by her to her daughter in 1844.