Located on the right bank of the Guadalimar river, the Ibero-Roman city of Cástulo was a major centre in the south of the Iberian peninsula in antiquity as a result of both its walled enclosure and its strategic position at the headwaters of the Guadalquivir valley. The city was prominent as a main hub on the communications routes of the time, and over its history, had privileged access to the Sierra Morena's mining resources. The oppidum (the fortified city) of Cástulo, at first, was the most important population centre in Iberian Oretania; later, it was given the status of a Roman municipium. It eventually became an episcopal see in the late imperial period.

Classical authors gave special recognition to Cástulo, particularly because of its key role during the Second Punic War, the conflict for control of the western Mediterranean that pitted Carthage against the Roman Republic. In fact, although it initially acquired importance because of its allegiance to the Carthaginian cause, Cástulo finally allied with Rome. This factor allowed it to maintain a unique political independence, as shown by its ability to mint coins in these circumstances which the local community used to produce its own symbols and writing.

The perimeter of the walled area covers 50 hectares on which we can identify different periods of occupation between the 3rd millennium BCE until the 1300s. In addition to the Iberian and Roman city and its different transformations until it was abandoned in the 14th century, evidence of Late Neolithic-Chalcolithic huts, pottery and flint tools from the Bronze Age has been found on this meseta, as well as a large settlement from the late Bronze Age which represented the beginnings of the city of Cástulo.

Surrounding the walled enclosures are necropolises, factories, public infrastructures, a port by the river Guadalimar and other suburban installations associated with the Ibero-Roman city, in addition to other settlements from prehistory to the modern times, all of which complete the significant heritage value of this archaeological site.

In 1956 the Monographic Museum of Cástulo was founded in Linares (Jaén) on the initiative of Rafael Contreras de la Paz; it was from this centre that research into the archaeological site was spearheaded. Conceived as a municipal museum, it was declared a National Artistic and Historic Monument in 1961 and the Decree of 21 March 1972 recognises the state's ownership of the museum, which became part of the National Museums Trust.

Linares Town Council bought and transferred to the state the Dávalos family palace, known as the Casa del Torreón, for use as a museum. After it was restored and opened on 23 September 1983, it became the site of the Archaeological Museum of Linares and the Monographic Museum of Cástulo.