Iserlohn (ēˌzərlōnˈ) [key], city (1994 pop. 98,480), North Rhine–Westphalia, W Germany. It is a commercial and industrial center. Its manufactures include metal goods, machinery, chemicals, and rubber and leather goods. Iserlohn became an important town in the 13th cent. and was known for the manufacture of armor, chains, and needles. Until the 19th cent. it was the largest city in Westphalia.