The Hellenistic theatre of the ancient city of Kedreai was built on a natural slope and, like the entire city, has not yet been explored and excavated.

Kedreai (Cedreae) is an ancient city on the island of the same name (today Sedir Adası) in the Gulf of Gokova. Today the island measures 900 meters in width and 300 meters in width.
The ancient ruins are located on the hilly eastern part of the island, divided by a narrow land bridge in the middle. On the north side of the hill, halfway up, lies the well-preserved theatre, which has not yet been excavated. There are also remains of the city wall, remains of the agora, a temple of Apollo and a Byzantine basilica. Other buildings and fortifications have been preserved on the neighbouring islands and on the nearby mainland. The necropolis of the city with tombs and sarcophagi is about 200 metres away on the mainland.

Historically not much is known about the city. The ancient Greek historian and geographer Hekataios of Miletus reported in the 6th century BC that Kedreai was a Carian city. It was a member of the Delaisch-Attic League. It is also said that the city was besieged by Spartan general Lysandros in 406 B.C. and taken the next day. The inhabitants were sold as slaves. During the reign of Emperor Vespasian, the Kedreaten erected a memorial for him, which unfortunately has not been preserved or excavated.