Ayvalık, formerly also known as Kydonies, is a municipality and district of Balıkesir Province, Turkey. Its area is 305 km2, and its population is 74,030 (2022). It is a seaside town on the northwestern Aegean coast of Turkey. The town centre is connected to Cunda Island by a causeway and is surrounded by the archipelago of Ayvalık Islands, which face the nearby Greek island of Lesbos.