Middletown [Middlesex County] was incorporated in 1651 and named in 1653 from its position on the Connecticut River between the upper river towns and Saybrook. Its Native American name is "Mattabeset".Area, 42.3 sq. miles. Population, est., 43,640. Voting districts, 10. Principal industries, information technology, switches, paper boxes, internet publishing, office machinery, aerospace products, tools and dies, metal and wire goods, brass hardware, heat elements, plastics, sheet metal, chemicals, jet engines and insurance.