Gonio fortress is a Roman fortification in Adjara, Georgia, on the Black Sea, 15 km south of Batumi, at the mouth of the Chorokhi river. The village sits 4 km north of the Turkish border. The oldest reference to the fortress is by Pliny the Elder in the Natural History (1st century AD). There is also a reference to the ancient name of the site in Appian’s Mithridatic Wars (2nd century AD). In the 2nd century AD it was a well-fortified Roman city within Colchis. The town was also known for its theatre and hippodrome. It later came under Byzantine influence. The name "Gonio" is first attested in Michael Panaretos in the 14th century. In addition, there was a short-lived Genoese trade factory at the site. In 1547 Gonio was taken by the Ottomans, who held it until 1878, when, via the San-Stefano Treaty, Adjara became part of the Russian empire.