The Forum was the nerve centre of Roman Tarraco. The city's main streets led to it and it was the focal point for all public activities. As such, it became the meeting place for the local elite, as well as being the administrative centre. It was, in summary, the centre of the social and political life of the colony.

Technically speaking, it was a large porticoed square containing the main administrative and religious buildings of Tarraco. It was divided into two areas: The worship area was presided over by a temple thought to have been dedicated to the Capitoline Triad - Jupiter, Juno and Minerva, or to Dea Roma, or to the deified emperor during a later period. The other area, of a commercial and political nature, centred around various buildings including the curia, where the ordo decurionum (city council) met, and the basilica. The archways surrounding the area were occupied by tabernae (shops). In the forum it was also common to find the local archive, other smaller temples, and statues dedicated to members of the Imperial family and other local dignitaries.

The Local Forum was located in the lower part of the Roman city, in the residential area, half way between the provincial administration sector and the port. Today it is delimited by Cardenal Cervantes, Lleida and Gasòmetre Streets.

The first city forum dates from the Republican era (2nd century BC), although we have practically no information about it. During the reign of Augustus (around the turn of the millennium), the complex was monumentalized. The basilica dates from this time.