Castillo de los Cornel, Medieval fortress in Alfajarín, Spain.

Castillo de los Cornel stands on a rocky spur above the Ebro, north of Alfajarín across the A-2. Its irregular pentagonal enclosure measures about 100 by 60 metres, with natural cliffs on the north and east and an artificial ditch elsewhere. The entrance had a drawbridge between two towers; one preserves a square plan about 6 metres wide and two pointed barrel vaults, while the 14th-century keep retains only two thick walls of brick-faced rammed earth.

The fortress was built by Muslims in the 11th century and changed hands multiple times between Islamic and Christian forces until its final conquest in 1141. After that point, it became an important position for Christian control in the region.

The castle's name comes from the Cornel barony, granted by James II of Aragon in 1293 and held until the line died out at the end of the 14th century. The site was later bought by figures such as Ramón de Espés and the Alagón family. Nearby, the hermitage of the Virgen de la Peña may echo the place name Alfajarín, thought to mean "the two rocks".

Access to the fortress is through the main entrance framed by the two towers, which serves as the natural orientation point. Since the site sits on a rocky hill, visitors should expect uneven terrain and bring appropriate footwear.

The castle's name comes from the Cornel barony, to which James II of Aragon granted it in 1293. The 14th-century homage tower, built of rammed earth faced with brick, now retains only two thick walls. Nearby stood the hermitage of the Virgen de la Peña, whose original gypsum rammed-earth walls matched the castle's.