The first reference to the site of Juromenha dates from the second half of the 9th century. For over two hundred years this place has been considered the stronghold for defence of the Badajoz area, belonging, since the 10th century, to the Caliphate of Cordoba. In 1167 D. Afonso Henriques conquered the fortress, but it would return to the Moorish domain in 1191 and would only be definitively regained by the Portuguese Crown in 1242. Later, in 1312, D. Dinis ordered the complete reconstruction of the fortress.

In the post-Restoration period, due to its strategic importance, the medieval fortress was adapted to the 17th century artillery, and works were carried out following the plan authored by Eng. Nicolau de Langres. From 1662 and for six years, it was occupied by the troops of King John of Austria, only returning to the possession of the Portuguese Crown in the General Peace of 1668.

With the 1755 earthquake the fortress was largely damaged, especially the 17th century building area, and has since been rebuilt. A fort was also built within the walls next to the Guadiana, to dock the barges. In the early 19th century, during the Peninsular War it was seized by the army of D. Manuel Godoy, and was only recaptured in 1808. It gradually fell into decay, and became being uninhabited in 1920.  In 1950 major works of recovery in the fortress began which lasted until 1996.

The fortress, with a polygonal floor plan, consists of two ramparts, one internal, where the keep is located, and another external, bastion type, with a star-shaped layout. In the inner space of the fortress the Church of Mercy and the Mother Church were built, as well as the old City Hall and its jail, and a rectangular cistern that supplied the population.

Today, inside the walled enclosure there are the ruins of the two churches, the jail and the old Town Hall. In terms of landscape, the old fortress has a privileged location with regards to the views of Portuguese and Spanish landscapes.