Gulf of İzmit

The gulf takes its name from the city of İzmit.

Other cities and towns around the bay are Gebze, Körfez, Gölcük, and Altınova.

In the east–west direction, it extends for a length of about 48 kilometres (30 mi), while in the north–south direction its width varies from 2 to 3 kilometres (1.2 to 1.9 mi) at the narrowest spots to about 10 kilometres (6.2 mi) at its widest.

The North Anatolian Fault Zone, the most prominent active fault in Turkey and the source of numerous large earthquakes throughout history, passes through the Gulf of İzmit.

[1] İzmit’s ancient names were Gulf of Astacus, Sinus Astacenus (Ancient Greek: Ἀστακηνὸς κόλπος),[2] Olbianus Sinus (Ancient Greek: Ὀλβιανὸς κόλπος, romanized: Olbianos kolpos),[3] and Gulf of Nicomedia.