Kaytazdere

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).

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.

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.

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

Sefine Shipyard (Turkish: Sefine Tersanesi) is located in Yalova Province, Turkey. It builds a wide variety of ships including tugboats, fireboats, passenger/car ferries and well boats.

Boğaziçi Shipyard (Turkish: Boğaziçi Tersanesi) is a Turkish shipyard established in Kadikoy, Istanbul, in 1992. The company's head office located in Istanbul, Turkey, new shipbuilding facilities located in Yalova Turkey.

Beșiktaș Shipyard (Turkish: Beșiktaș Tersanesi) is a Turkish shipyard established in Altınova, Yalova in 2007.

The Osmangazi Bridge (Turkish: Osmangazi Köprüsü) is a suspension bridge spanning the Gulf of İzmit at its narrowest point, 2,620 m (8,600 ft). The bridge links the Turkish city of Gebze to the Yalova Province and carries the O-5 motorway across the gulf. The bridge was opened on 1 July 2016 to become the then-longest suspension bridge in Turkey and the fourth-longest (seventh-longest as of 2023) suspension bridge in the world by the length of its central span. The length of the bridge was surpassed by the Çanakkale 1915 Bridge across the Dardanelles strait, which became the longest suspension bridge in the world when it was opened on 18 March 2022.

Karapınar is a neighbourhood of the municipality and district of Karamürsel, Kocaeli Province, Turkey. Its population is 581 (2022). It is 37 km from İzmit city center and 5 km from 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.