Polymedium or Polymedion (Ancient Greek: Πολυμήδειον), also known as Palamedium or Polymedia, was a small town in ancient Aeolis, between the promontory Lectum and Assus, and at a distance of 40 stadia from the former.
Its site is located near Asarlık, Asiatic Turkey.
The Edremit gulf (Turkish: Edremit körfezi) is an Aegean gulf in Turkey's Balıkesir Province. It is named after Edremit, a district of Balıkesir Province which is situated close to the tip of the gulf. Biga Peninsula is to the north. The southern coast belongs to the ilçe of Ayvalık, while the western entrance is enclosed with the northern part of the Greek island of Lesbos.
In ancient history there were many settlements lying close to the north coast of the gulf; Hamaxitus, Polymedium, Assos, Lamponeia, Antandrus and Adramyttion, were some of these.