Louisa Stanhope, Countess Stanhope

Louisa Stanhope, Countess Stanhope (28 July 1758 – 7 March 1829), was born Louisa Grenville. She was the daughter and sole heiress of Henry Grenville, a diplomat and politician, and his wife Margaret Eleanor Banks. Henry Grenville was a younger brother of Richard Grenville-Temple, 2nd Earl Temple, and George Grenville, who served as Prime Minister of Great Britain.

In 1781, Louisa Grenville married Charles Stanhope, who would become the 3rd Earl Stanhope. The marriage took place on 19 March 1781, less than a year after the death of Stanhope's first wife, Hester, who was Louisa’s first cousin. Hester was the daughter of her grandmother, Hester Pitt, Countess of Chatham, who was a sister of Henry Grenville.

Louisa and Charles Stanhope had three sons: Philip Henry Stanhope (1781–1855), who succeeded as the 4th Earl Stanhope; Charles Banks Stanhope (1785–1809), who served as aide-de-camp to Sir John Moore and was killed during the Battle of Corunna; and James Hamilton Stanhope (1788–1825), who held the rank of lieutenant-colonel and was a captain in the 1st Foot Guards. James Stanhope married Frederica-Louisa William, daughter of the 3rd Earl Mansfield, and they had one child.

Charles Stanhope inherited the earldom in 1786, upon the death of his predecessor, making Louisa the Countess Stanhope. Records from 1806, notably by Joseph Farington, indicate that Stanhope's behavior toward his wife was such that she obtained a separate maintenance, and that Stanhope had settled £1,500 annually on her to avoid accusations of adultery. Louisa was involved with a music tutor, Mrs. Walburga Lackner, who had been employed to teach her children; in Stanhope’s will, Lackner was also left money.

Louisa Stanhope died at her residence in Clarges Street, London, at the age of 70, after a long illness. Upon her death, John Pitt, 2nd Earl of Chatham, sent a letter of condolence to her eldest son on 10 March 1829.