Cherbourg (shĕrbōrˈ) [key], city (1990 pop. 28,773), Manche dept., NW France, in Normandy, on the English Channel, at the tip of the Cotentin peninsula. It is a naval base and seaport, and a major industrial center where submarines, oil tankers and platforms, electronics, and metals are manufactured. The site has been settled since ancient times and was frequently fought over by the French and English because of its strategic value. Fortifications were begun under Louis XIV.