Constantine, city, northeastern Algeria, capital of Constantine Province. It is a center for the manufacture of leather and leather goods and woolen and linen goods. It has considerable trade in these products and in cereal grains with Algiers, Tunis, Annaba, Biskra, and Skikda, the last-named serving as the port of Constantine.
The city, built in AD313 by the Roman emperor Constantine the Great on the site of the ancient Numidian city of Cirta, stands on a rocky plateau, more than 640 m (2100 ft) above sea level. It is cut off from the surrounding country on all sides except the west by a deep ravine, through which the Rhumel River flows. A viaduct spans the ravine in the south, and bridges cross it in the north and northeast.
