Newcastle-under-Lyme, city (1991 pop. 73,208) and district, Staffordshire, W central England, on the Lyme River. Construction materials, apparel, computers, electric motors, and machinery are manufactured in the city. There are ruins of a castle built (12th cent., the "new castle" of the city's name) under Ranulf, earl of Chester. The 13th-century parish church was redesigned in 1876 by George Gilbert Scott. Within the district, Chesterton has extensive Roman remains.