Coordinates: 35°29′20″N 06°15′21″E / 35.48889°N 6.25583°E / 35.48889; 6.25583

Lambaesis, or Lambaesa, is a Roman ruin in Algeria, 7 miles (11 km) southeast of Batna and 17 miles (27 km) west of Timgad, located next to the modern village of Tazoult.

The remains of the Roman town, and more especially of the Roman camp, in spite of wanton vandalism, are among the most interesting ruins in northern Africa. The ruins are situated on the lower terraces of the Aures Mountains, and consist of triumphal arches (one to Septimius Severus, another to Commodus), temples, aqueducts, vestiges of an amphitheatre, baths and an immense quantity of masonry belonging to private houses. To the north and east lie extensive cemeteries with the stones standing in their original alignments; to the west is a similar area, from which, however, the stones have been largely removed for building the modern village.

Of the temple of Aesculapius only one column is standing, though in the middle of the 19th century its façade was entire. The capitol or temple dedicated to Jupiter, Juno and Minerva, which has been cleared of debris, has a portico with eight columns. On level ground about two-thirds of a mile from the centre of the ancient town stands the camp, its site now partly occupied by the penitentiary and its gardens. It measures 1,640 feet (500 m) by 1,476 feet (450 m), and in the middle rise the ruins of a building commonly called, but incorrectly, the praetorium. This noble building, which dates from 268, is 92 feet (28 m) long by 66 feet (20 m) broad and 49 feet (15 m) high; its southern façade has a splendid peristyle half the height of the wall, consisting of a front row of massive Ionic columns and an engaged row of Corinthian pilasters.