Somerville. 1 City (1990 pop. 76,210), Middlesex co., E Mass., a residential and industrial suburb of Boston, on the Mystic River; settled 1630, set off from Charlestown 1842, inc. as a city 1871. There are diverse light manufactures, including chemicals. Historical attractions include the Old Powder House, used in the American Revolution; Prospect Hill Tower, where General Israel Putnam raised the first flag of the united colonies (1776) and which served as a prison camp in the Civil War; and Ploughed Hill, one of the fortified hills used in the siege of Boston (1775). 2 Residential borough (1990 pop. 11,632), seat of Somerset co., N central N.J., on the Raritan River; settled 1683, inc. as a borough 1909. Electronic parts and pharmaceuticals are made. Of interest are the Wallace House (residence of George Washington 1778–79) and the old Dutch parsonage (1751; now a museum).