ACERRA, town and episcopal see, province of Naples, Italy, 9m. N.E. from Naples. Pop. (1931) 20,112 (town), 21,165 (commune). The town lies on the right bank of the river Agno, Soft. above sea, in a fertile but . somewhat marshy district, formerly malarious. It became a city with Latin rights in 332 B.C. ; was destroyed by Hannibal (216 B.c.) ; restored (210); served as Roman headquarters in the Social War (90).