Iulia Valentia Banasa was a Roman city in northern Morocco. It was one of the three colonias in Mauretania Tingitana founded by emperor Augustus between 33 and 25 BC for veterans of the battle of Actium.
Iulia Valentia Banasa was located on the southern bank of the Sebou River on the site now known as Sidi Ali Boujenoun. At the start of the reign of Marcus Aurelius, Banasa became Colonia Aurelia Banasa. In 285 AD, the Roman province of Mauretania Tingitana was reduced to the territories located north of the Lixus. Banasa was then abandoned.
Among the stone ruins at Iulia Valentia Banasa are some characteristic elements of ancient Roman architecture: a forum with a basilica, capitol and baths, as well as streets in a regular pattern. Many of the buildings date from the early third century AD. Beautiful mosaics decorated the buildings and now most are shown at the Rabat archeological museum
The Latin name Valentia means young, strong and may be compared to Valence (France) and Valencia (Spain), also colonies. Augustus founded at least twelve Roman colonias in Mauretania, although it was a client-kingdom and not yet a province of the empire. Some of the other major Roman companion cities to Iulia Valentia Banasa of this early era are Chellah and Volubilis, the latter of which shares the features of basilica and regular street pattern.
Objects recovered at Banasa may be seen at the Rabat Archaeological Museum.