Castell de Llers is a 13th-century fortress in Alt Empordà, Girona, which once anchored a network of twelve dependent castles forming a crucial medieval defense system. Built in the Romanesque tradition with a central tower and rectangular walled enclosure, the castle originated from strategic importance dating to the 10th century when it marked the border between the counties of Besalú and Empúries. Though heavily damaged during the Spanish Civil War, restoration efforts between 1981 and 2013 have preserved the tower and walled remains, which visitors can explore to observe the structural ruins and internal room vestiges within the fortification.