Wills Hill, 1st Marquess of Downshire (30 May 1718 - 7 October 1793), was a British politician of the Georgian era. He was usually called the Earl of Hillsborough in America when he served as Secretary of State for the Colonies in 1768-1772, a critical period leading toward the American Revolution. (Hillsborough County, New Hampshire and Hillsborough County, Florida in the United States are named in his honor.)

The son of Trevor Hill, 1st Viscount Hillsborough, he was born at Fairford in Gloucestershire. He became an English member of parliament in 1741, and an Irish viscount on his father's death in the following year, thus sitting in both the English and Irish parliaments. In 1751 he was created Earl of Hillsborough in the Irish peerage; in 1754 he was made Comptroller of the Royal Household and an English privy councillor; and in 1756 he became a peer of Great Britain as Baron Harwich.

For nearly two years he was President of the Board of Trade and Plantations under George Grenville, and after a brief period of retirement he filled the same position, and then that of joint Postmaster-General, under the Earl of Chatham. From 1768 to 1772 Hillsborough was Secretary of State for the Colonies and also president of the board of trade, becoming an English earl on his retirement; in 1779 he was made Secretary of State for the Southern Department, and he was created Marquess of Downshire seven years after his final retirement in 1782. Both in and out of office he opposed all concessions to the American colonists, but he favored the project for a union between England and Ireland. Reversing an earlier opinion, Horace Walpole says Downshire was a pompous composition of ignorance and want of judgment. He died on 7 October 1793 and was succeeded by his son Arthur (1753-1801).