Populated places in Bithynia

Nicaea (also spelled Nicæa or Nicea, ; ), also known as Nikaia (, Attic: , Koine: ) or Nice ( or ), was an ancient Greek city in the northwestern Anatolian region of Bithynia.

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.

ancient city of Bithynia in modern-day Turkey

ancient city of Bithynia in modern-day Turkey

thumb|upright=1.5|The location of Hellespontine Phrygia, and the provincial capital of Dascylium, in the [[Achaemenid Empire, c. 500 BC.]] Dascylium, Dascyleium, or Daskyleion (), also known as Dascylus, was a town in Anatolia some inland from the coast of the Propontis, at modern Ergili, Turkey. Its site was rediscovered in 1952 and has since been excavated.

ancient city of Bithynia in modern-day Turkey

Basilinopolis or Basilinoupolis (Greek: Βασιλινούπολις) was a town in Bithynia Prima (civil Diocese of Pontus), which obtained the rank of a city under, or perhaps shortly before, Roman Emperor Julian the Apostate, whose mother was Basilina.

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 on the Bosphorus opposite Istanbul

Hieria (in Greek variously ), also known as Heraeum or Heraion (Ἡραῖον), modern Fenerbahçe, was a town of ancient Bithynia and a suburb of Byzantine-era Constantinople (modern Istanbul, Turkey). It is prominent in the city's history as the site of an imperial palace.

thumb|Bithynia marked in radium green Gordoservon or Gordoserbon or Gordoserba (; ) was an early medieval Byzantine city, and a bishopric, suffragan of the Metropolis of Nicaea, in the region of Bithynia, Asia Minor. It is mentioned in several ecclesiastical sources from the period between the 7th and the 9th century. Most notably, the city is mentioned in the acts of the Council of Trullo (691-692), as a seat of bishop Isidore, who attended the council.

ruined city located in Düzce Province

ancient city of Bithynia, in modern-day Turkey

Juliopolis or Ioulioupolis (), occasionally also Heliopolis (Ἡλιούπολις), was an ancient and medieval city and episcopal see in Anatolia (modern Turkey). In later Byzantine times, it also bore the name Basilaion (Βασιλαίον). Various authors assign it to the regions of Galatia, Bithynia, and Paphlagonia. Now, it is in the province of Ankara, Nallıhan.

Bithynium or Bithynion () was an ancient city in Bithynia. Its site is occupied by the modern town of Bolu, Asiatic Turkey.

mahalle (administrative quarter) in Kandıra, Kocaeli, northwestern Turkey

ancient city of Bithynia in modern-day Turkey