Nashua (năshˈōə) [key], city (1990 pop. 79,662), seat of Hillsborough co., S N.H., on the Merrimack and Nashua rivers near the Mass. line; settled c.1655, inc. as a city 1853. Because of the availability of water power, Nashua developed (early 19th cent.) as a textile mill town; the closing of these mills after World War II prompted the development of diverse manufacturing. Chief among Nashua's products are machinery; rubber, wood, metal, paper, and plastic products; building materials; computers; transportation equipment; electrical and electronic goods; furniture; chemicals; shoes; air shafts; and defense systems. The city has grown as a satellite community of the Boston metropolitan area. It is the seat of Rivier College and Daniel Webster College. The Federal Aviation Administration has a traffic control center there.