Jonathan Mason (September 12, 1756 – November 1, 1831) was a Federalist United States Senator and Representative from Massachusetts during the early years of the United States. Mason was born in Boston in the Province of Massachusetts Bay. He attended Boston Latin School the College of New Jersey (now Princeton University), graduating in 1774. After studying law, he was admitted to the bar in 1779. On April 13, 1779, Mason married Susannah Powell (1761–1836). They had seven children—five daughters and two sons: In 1780, Mason delivered the annual address marking the Boston Massacre.