Greek colonies in Bithynia

Zonguldak () is a city of about 100,000 people in the Black Sea region of Turkey. It is the seat of Zonguldak Province and Zonguldak District. It was established in 1849 as a port town for the nearby coal mines in Ereğli. The current mayor is Tahsin Erdem, representing the CHP.

Nicomedia (; , Nikomedeia; modern İzmit) was an ancient Greek city located in what is now Turkey. In 286 AD, Nicomedia became the eastern and most senior capital city of the Roman Empire (chosen by the emperor Diocletian who ruled in the east), a status which the city maintained during the Tetrarchy system (293–324 AD).

Chalcedon (; ) was an ancient maritime town of Bithynia, in Asia Minor. It was located almost directly opposite Byzantium, south of Scutari (modern Üsküdar) and it is now a district of the city of Istanbul named Kadıköy. The name Chalcedon is a variant of Calchedon, found on all the coins of the town as well as in manuscripts of Herodotus's Histories, Xenophon's Hellenica, Arrian's Anabasis, and other works. Except for the Maiden's Tower, almost no above-ground vestiges of the ancient city survive in Kadıköy today; artifacts uncovered at Altıyol and other excavation sites are on display at the

ancient city of Bithynia in modern-day Turkey

Cius (; Kios) was an Ancient Greek city bordering the Propontis (now known as the Sea of Marmara), in Bithynia and in Mysia (in modern northwestern Turkey). The city was later renamed to Prusias after King Prusias I of Bithynia, who once restored the city.

Tium () was an ancient settlement, also known as Filyos (), on the south coast of the Black Sea at the mouth of the river Billaeus in present-day Turkey. Ancient writers variously assigned it to ancient Paphlagonia or Bithynia.

ancient city of Bithynia in modern-day Turkey