The city of Kairouan, the capital of the Aghlabides Dynasty (A.D. 800–909), and its surrounding areas were affected by a damaging earthquake on 8 Rajab 245 Hijri (9 October 859). Contemporaneous accounts by local travelers to the Abassides Califat (A.D. 750–1258) and reported by the chroniclers and historians Al Baghdadi (1980) and Al Tabari (A.D. 838–923) (1967) describe the damage to the city and report that 13 villages experienced extensive destruction, leading to a large number of people homeless. In the city of Kairouan, the dome and other holy places of the Great Mosque (minbar and mihrab), houses, fortifications, and bridges all suffered severe damage. The aqueduct that supplied Kairouan with fresh water from the western mountains was badly damaged at a location about 20 km west of the city. New archaeoseismic field investigations of the aqueduct using laser scanning and radiocarbon dating characterize the damaged features. Recent field investigations in the region taking into account the construction types and the inferred damage distribution suggest a macroseismic intensity reaching IX–X Medvedev–Sponhauer–Karnik scale. The seismotectonic context suggests a seismic source along the major Sbiba east–west‐trending transpressive fault that includes the Cherichira, Sfaia, and El Baten folding system near Kairouan. An active fault system affecting late Quaternary units made up of thrust‐related en echelon folds associated with the east–west‐trending fault is identified and characterized as seismogenic at a location about 20 km west of Kairouan.