born Aug. 29, 1780, Philadelphia, Pa., U.S.
died July 30, 1859, Philadelphia
U.S. diplomat.
The son of Benjamin Rush , he served as U.S. attorney general (181417) and secretary of the treasury (182529). As acting secretary of state (1817), he negotiated the Rush-Bagot Agreement with Britain, which limited naval forces on the Great Lakes after the War of 1812. As U.S. minister to Britain (181725), he negotiated an agreement fixing the border between Canada and the U.S. at the 49th parallel. In conferences on Latin America, he helped formulate the Monroe Doctrine . In 1836, as the U.S. agent in London, he received the bequest by which James Smithson founded the Smithsonian Institution ; Rush considered his role in founding the museum his most important public service.