an Algerian village notable for its Roman ruins; it is located in the Batna département, 80 miles (128 km) south-southwest of Constantine by road.

The remains of the Roman town (Lambaesis) and camp include two triumphal arches, temples, an aqueduct, an amphitheatre, baths, and many private houses. The camp of the third legion, charged with defending North Africa, was moved to Lambessa between AD 123 and 129. Its remains, located north of the modern village, are dominated by a praetorium (commandant's house) dating from AD 268. Lambaesis became a town during the reign of Marcus Aurelius (AD 161–180) and the capital of the Roman province of Numidia under the emperor Septimius Severus (Severus, Septimius) (AD 193–211). With the departure of the legion in 392 the ancient town soon declined.

The modern settlement was founded in 1848 by French agriculturalists attracted by the fertile soil. A large convict prison for French political deportees was established there in 1852. Pop. (latest est.) 16,057.