El Castillo del Rio is a 12th-century Almoravide fortress located near Aspe in Alicante, Spain, built on a hillside overlooking the confluence of the Tarafa and Vinalopó rivers. Originally known as "Aspe el Viejo," the castle served as the primary settlement for the region for approximately 150 years until the late 13th century, when residents gradually relocated to the town below. The fortification features a large walled enclosure of about 7,000 square meters with twelve towers but no central keep, reflecting Islamic military architecture. Today the remains are partially ruined but protected as a cultural monument, offering views across the surrounding Valencian landscape from its strategic hilltop position.