Longwy (lôNwēˈ) [key], town (1990 pop. 15,647), Meurthe-et-Moselle dept., NE France, near the Belgian and Luxembourg borders. The center of the Lorraine iron and steel industry, Longwy has been diversifying its economic base into ceramics and steel products. Longwy-Haut, c.500 ft (150 m) higher, has kept the fortifications built (17th cent.) by Vauban.