This was the site on which the settlement of Aljezur grew during the Islamic period, although archaeological finds show that the summit was occupied as far back as the Bronze Age, and there is evidence of continuous occupation until the Early Modern Period.
Built in stone, the multi-sided castle is well adapted to the terrain. A semi-circular turret was built against the north wall and a square tower against the south wall. Inside, there is a cistern and the ruins of a cluster of dwellings that were used during the Christian mediaeval period.
Part of the defensive system of Silves in the 12th and 13th century, the Castle of Aljezur was incorporated into Portuguese territory when, as a result of the Christian reconquest, it passed into the hands of the Order of St James of the Sword. Its strategic importance gradually diminished over time and in the 16th century it had already been abandoned. The walls were partially rebuilt during the 1940s.