Karapınar, Karamürsel

Karamürsel is a municipality and district of Kocaeli Province, Turkey. Its area is 262 km2, and its population is 59,676 (2022). It is on the south coast of the Gulf of İzmit. Before its conquest by the Ottomans it used to be called by the Greek name of Praenetos (Πραινετός in Greek). The modern name commemorates Kara Mürsel who founded the Ottoman navy and designed distinctive galley ships, called kadırgas, for it.Karamürsel holds special significance for the Turkish Navy, as it was here in 1323 that the Ottoman Empire first established an outlet to the sea, thus laying the foundations for the Ottoman Navy which would go on to dominate the eastern Mediterranean for several centuries. The Karamürsel area is not as heavily industrialised as other parts of Kocaeli province,. Ferry services link Karamürsel to İzmit and Hereke on the northern side of the Bay of İzmit.

Praenetus or Prainetos (Ancient Greek: Πραίνετος), also known as Prinetos or Prinetus (Πρίνετος) was a town of ancient Bithynia on the coast of the Propontis. It on the north side of Mount Arganthonius (Samanli Daği), and at the southern entrance of the Sinus Astacenus. It was situated 28 Roman miles to the northwest of Nicaea. Stephanus of Byzantium calls it Pronectus or Pronektos (Πρόνεκτος) and states that it was founded by the Phoenicians. If this be true, it would be a very ancient place, which can scarcely be conceived, as it is mentioned only by very late writers. According to Cedrenus it was destroyed by an earthquake. It was a bishopric; no longer the seat of a residential bishop, it remains a titular see of the Roman Catholic Church.Its site is located near Karamürsel, in Asiatic Turkey.

Kaytazdere is a town (belde) in the Altınova District, Yalova Province, Turkey. Its population is 6,873 (2022). It is almost merged to Altınova. Distance to Yalova is 25 kilometres (16 mi). The settlement was founded at the end of the second Balkan War by Turkish refugees from Bulgaria. After the second World War an airbase was established around Kaytazdere. The economy of the town depends on small industries and agriculture.

Gulf of İzmit (Turkish: İzmit Körfezi), also referred to as Izmit Bay, is a bay at the easternmost edge of the Sea of Marmara, in Kocaeli Province, Turkey. 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 İzmit Bay Bridge is a suspension bridge that bridges the gulf. 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.

Altınova District is a district of the Yalova Province of Turkey. Its seat is the town of Altınova. Its area is 113 km2, and its population is 32,207 (2022).

Altınova is a town in Yalova Province in the east of Marmara region of Turkey. It is the seat of Altınova District. Its population is 9,042 (2022). The mayor is Metin Oral (AK Party).

Tavşancıl railway station was a railway station in Tavşancıl, Turkey on the Istanbul-Ankara railway. It was located in the southern part of the town on the shore of the Gulf of İzmit. The station was a stop on the Adapazarı Express regional train service; 11 daily eastbound trains and 13 daily westbound trains stopped at Tavşancıl. The opening date of the station is unclear, but the station was rebuilt and expanded in 1975, when the Turkish State Railways double-tracked the railway from Gebze to Arifiye. Tavşancıl station closed on 1 February 2012 and the platforms were demolished shortly after.

Subaşı is a town (belde) in the Altınova District, Yalova Province, Turkey. Its population is 8,281 (2022). It is close to Hersek Headland of Marmara Sea and has almost merged to Altınova to the east. The distance to Yalova is 12 kilometres (7.5 mi). The name of the village refers to subaşi, a title in the Ottoman bureaucracy and the residents of the town are mostly Turkish, Tatar and Gagauz migrants who left Dobrudzha and Deliorman area in Romania today Bulgaria around 1935. The settlement was declared a seat of township in 1992. It suffered severely in the 7.6 magnitude 1999 İzmit earthquake.

Hersek headland (Turkish: Hersek burnu) is a headland in Turkey.

The Hereke Tunnel (Turkish: Hereke Tüneli), is a motorway tunnel constructed on the Istanbul–Ankara motorway O-4 E80 in Kocaeli Province, northwestern Turkey. It was opened to traffic in 1984. It is situated in Körfez district of Kocaeli Province. The 281–285-metre (922–935 ft) long twin-tube tunnel carries three lanes of traffic in each direction. The tunnel was constructed in the 1980s. During the 1999 İzmit earthquake, the tunnel was light damaged. In 2012, the tunnel's both tubes were reinforced. In the time period of 2013–2014, the tunnel was modernized for traffic safety. Around 55,000 vehicles pass through the tunnel in both directions daily.

Limnae or Limnai (Ancient Greek: Λίμναι) was a town of ancient Bithynia on the coast of the Propontis. It was a colony of Miletus.Its site is located near Hersek, in Asiatic Turkey.

Helenopolis (Greek: Ἑλενόπολις) or Drepana (Δρέπανα) or Drepanon (Δρέπανον) was an ancient Greco-Roman and Byzantine town in Bithynia, Asia Minor, on the southern side of the Gulf of Astacus. It has been identified with the modern village of Hersek, in the district of Altınova, Yalova Province. It is traditionally considered as the birthplace of Saint Helena.